ThreeCSG_uncompressed_modified.js

var ThreeCSG = (function () {
   'use strict';
   /*

   ## IMPORTANT NOTE --- IMPORTANT 
   The master for this file is located at:
   https://github.com/joostn/openjscad/tree/gh-pages
   That is the gh-pages branch of the joostn/openjscad project
   If contributing from openjscad.org, please do NOT edit this local file but make pull requests against
   above joostn/gh-pages branch.
   ## IMPORTANT NOTE --- IMPORTANT NOTE


   ## License

   Copyright (c) 2014 bebbi (elghatta@gmail.com)
   Copyright (c) 2013 Eduard Bespalov (edwbes@gmail.com)
   Copyright (c) 2012 Joost Nieuwenhuijse (joost@newhouse.nl)
   Copyright (c) 2011 Evan Wallace (http://evanw.github.com/csg.js/)
   Copyright (c) 2012 Alexandre Girard (https://github.com/alx)

   All code released under MIT license

   ## Overview

   For an overview of the CSG process see the original csg.js code:
   http://evanw.github.com/csg.js/

   CSG operations through BSP trees suffer from one problem: heavy fragmentation
   of polygons. If two CSG solids of n polygons are unified, the resulting solid may have
   in the order of n*n polygons, because each polygon is split by the planes of all other
   polygons. After a few operations the number of polygons explodes.

   This version of CSG.js solves the problem in 3 ways:

   1. Every polygon split is recorded in a tree (CSG.PolygonTreeNode). This is a separate
   tree, not to be confused with the CSG tree. If a polygon is split into two parts but in
   the end both fragments have not been discarded by the CSG operation, we can retrieve
   the original unsplit polygon from the tree, instead of the two fragments.

   This does not completely solve the issue though: if a polygon is split multiple times
   the number of fragments depends on the order of subsequent splits, and we might still
   end up with unncessary splits:
   Suppose a polygon is first split into A and B, and then into A1, B1, A2, B2. Suppose B2 is
   discarded. We will end up with 2 polygons: A and B1. Depending on the actual split boundaries
   we could still have joined A and B1 into one polygon. Therefore a second approach is used as well:

   2. After CSG operations all coplanar polygon fragments are joined by a retesselating
   operation. See CSG.reTesselated(). Retesselation is done through a
   linear sweep over the polygon surface. The sweep line passes over the y coordinates
   of all vertices in the polygon. Polygons are split at each sweep line, and the fragments
   are joined horizontally and vertically into larger polygons (making sure that we
   will end up with convex polygons).
   This still doesn't solve the problem completely: due to floating point imprecisions
   we may end up with small gaps between polygons, and polygons may not be exactly coplanar
   anymore, and as a result the retesselation algorithm may fail to join those polygons.
   Therefore:

   3. A canonicalization algorithm is implemented: it looks for vertices that have
   approximately the same coordinates (with a certain tolerance, say 1e-5) and replaces
   them with the same vertex. If polygons share a vertex they will actually point to the
   same CSG.Vertex instance. The same is done for polygon planes. See CSG.canonicalized().


   Performance improvements to the original CSG.js:

   Replaced the flip() and invert() methods by flipped() and inverted() which don't
   modify the source object. This allows to get rid of all clone() calls, so that
   multiple polygons can refer to the same CSG.Plane instance etc.

   The original union() used an extra invert(), clipTo(), invert() sequence just to remove the
   coplanar front faces from b; this is now combined in a single b.clipTo(a, true) call.

   Detection whether a polygon is in front or in back of a plane: for each polygon
   we are caching the coordinates of the bounding sphere. If the bounding sphere is
   in front or in back of the plane we don't have to check the individual vertices
   anymore.


   Other additions to the original CSG.js:

   CSG.Vector class has been renamed into CSG.Vector3D

   Classes for 3D lines, 2D vectors, 2D lines, and methods to find the intersection of
   a line and a plane etc.

   Transformations: CSG.transform(), CSG.translate(), CSG.rotate(), CSG.scale()

   Expanding or contracting a solid: CSG.expand() and CSG.contract(). Creates nice
   smooth corners.

   The vertex normal has been removed since it complicates retesselation. It's not needed
   for solid CAD anyway.

   */

   var _CSGDEBUG = false

   function fnNumberSort(a, b) {
     return a - b
   }
   // # class CSG
   // Holds a binary space partition tree representing a 3D solid. Two solids can
   // be combined using the `union()`, `subtract()`, and `intersect()` methods.
   var CSG = function () {
     this.polygons = []
     this.properties = new CSG.Properties()
     this.isCanonicalized = true
     this.isRetesselated = true
   }
   CSG.defaultResolution2D = 32
   CSG.defaultResolution3D = 12
   // Construct a CSG solid from a list of `CSG.Polygon` instances.
   CSG.fromPolygons = function (polygons) {
     var csg = new CSG()
     csg.polygons = polygons
     csg.isCanonicalized = false
     csg.isRetesselated = false
     return csg
   }
   // Construct a CSG solid from generated slices.
   // Look at CSG.Polygon.prototype.solidFromSlices for details
   CSG.fromSlices = function (options) {
     return (new CSG.Polygon.createFromPoints([
       [0, 0, 0],
       [1, 0, 0],
       [1, 1, 0],
       [0, 1, 0]
     ])).solidFromSlices(options)
   }
   // create from an untyped object with identical property names:
   CSG.fromObject = function (obj) {
     var polygons = obj.polygons.map(function (p) {
       return CSG.Polygon.fromObject(p)
     })
     var csg = CSG.fromPolygons(polygons)
     csg = csg.canonicalized()
     return csg
   }
   // Reconstruct a CSG from the output of toCompactBinary()
   CSG.fromCompactBinary = function (bin) {
     if (bin['class'] !== "CSG") throw new Error("Not a CSG")
     var planes = [],
       planeData = bin.planeData,
       numplanes = planeData.length / 4,
       arrayindex = 0,
       x, y, z, w, normal, plane
     for (var planeindex = 0; planeindex < numplanes; planeindex++) {
       x = planeData[arrayindex++]
       y = planeData[arrayindex++]
       z = planeData[arrayindex++]
       w = planeData[arrayindex++]
       normal = CSG.Vector3D.Create(x, y, z)
       plane = new CSG.Plane(normal, w)
       planes.push(plane)
     }
     var vertices = [],
       vertexData = bin.vertexData,
       numvertices = vertexData.length / 3,
       pos, vertex
     arrayindex = 0
     for (var vertexindex = 0; vertexindex < numvertices; vertexindex++) {
       x = vertexData[arrayindex++]
       y = vertexData[arrayindex++]
       z = vertexData[arrayindex++]
       pos = CSG.Vector3D.Create(x, y, z)
       vertex = new CSG.Vertex(pos)
       vertices.push(vertex)
     }
     var shareds = bin.shared.map(function (shared) {
       return CSG.Polygon.Shared.fromObject(shared)
     })
     var polygons = [],
       numpolygons = bin.numPolygons,
       numVerticesPerPolygon = bin.numVerticesPerPolygon,
       polygonVertices = bin.polygonVertices,
       polygonPlaneIndexes = bin.polygonPlaneIndexes,
       polygonSharedIndexes = bin.polygonSharedIndexes,
       numpolygonvertices, polygonvertices, shared, polygon //already defined plane,
     arrayindex = 0
     for (var polygonindex = 0; polygonindex < numpolygons; polygonindex++) {
       numpolygonvertices = numVerticesPerPolygon[polygonindex]
       polygonvertices = []
       for (var i = 0; i < numpolygonvertices; i++) {
         polygonvertices.push(vertices[polygonVertices[arrayindex++]])
       }
       plane = planes[polygonPlaneIndexes[polygonindex]]
       shared = shareds[polygonSharedIndexes[polygonindex]]
       polygon = new CSG.Polygon(polygonvertices, shared, plane)
       polygons.push(polygon)
     }
     var csg = CSG.fromPolygons(polygons)
     csg.isCanonicalized = true
     csg.isRetesselated = true
     return csg
   }
   CSG.prototype = {
     toPolygons: function () {
       return this.polygons
     },
     // Return a new CSG solid representing space in either this solid or in the
     // solid `csg`. Neither this solid nor the solid `csg` are modified.
     //
     //     A.union(B)
     //
     //     +-------+            +-------+
     //     |       |            |       |
     //     |   A   |            |       |
     //     |    +--+----+   =   |       +----+
     //     +----+--+    |       +----+       |
     //          |   B   |            |       |
     //          |       |            |       |
     //          +-------+            +-------+
     //
     union: function (csg) {
       var csgs
       if (csg instanceof Array) {
         csgs = csg.slice(0)
         csgs.push(this)
       } else {
         csgs = [this, csg]
       }
       // combine csg pairs in a way that forms a balanced binary tree pattern
       for (var i = 1; i < csgs.length; i += 2) {
         csgs.push(csgs[i - 1].unionSub(csgs[i]))
       }
       return csgs[i - 1].reTesselated().canonicalized()
     },
     unionSub: function (csg, retesselate, canonicalize) {
       if (!this.mayOverlap(csg)) {
         return this.unionForNonIntersecting(csg)
       } else {
         var a = new CSG.Tree(this.polygons)
         var b = new CSG.Tree(csg.polygons)
         a.clipTo(b, false)
           // b.clipTo(a, true); // ERROR: this doesn't work
         b.clipTo(a)
         b.invert()
         b.clipTo(a)
         b.invert()
         var newpolygons = a.allPolygons().concat(b.allPolygons())
         var result = CSG.fromPolygons(newpolygons)
         result.properties = this.properties._merge(csg.properties)
         if (retesselate) result = result.reTesselated()
         if (canonicalize) result = result.canonicalized()
         return result
       }
     },
     // Like union, but when we know that the two solids are not intersecting
     // Do not use if you are not completely sure that the solids do not intersect!
     unionForNonIntersecting: function (csg) {
       var newpolygons = this.polygons.concat(csg.polygons)
       var result = CSG.fromPolygons(newpolygons)
       result.properties = this.properties._merge(csg.properties)
       result.isCanonicalized = this.isCanonicalized && csg.isCanonicalized
       result.isRetesselated = this.isRetesselated && csg.isRetesselated
       return result
     },
     // Return a new CSG solid representing space in this solid but not in the
     // solid `csg`. Neither this solid nor the solid `csg` are modified.
     //
     //     A.subtract(B)
     //
     //     +-------+            +-------+
     //     |       |            |       |
     //     |   A   |            |       |
     //     |    +--+----+   =   |    +--+
     //     +----+--+    |       +----+
     //          |   B   |
     //          |       |
     //          +-------+
     //
     subtract: function (csg) {
       var csgs
       if (csg instanceof Array) {
         csgs = csg
       } else {
         csgs = [csg]
       }
       var result = this
       for (var i = 0; i < csgs.length; i++) {
         var islast = (i === (csgs.length - 1))
         result = result.subtractSub(csgs[i], islast, islast)
       }
       return result
     },
     subtractSub: function (csg, retesselate, canonicalize) {
       var a = new CSG.Tree(this.polygons)
       var b = new CSG.Tree(csg.polygons)
       a.invert()
       a.clipTo(b)
       b.clipTo(a, true)
       a.addPolygons(b.allPolygons())
       a.invert()
       var result = CSG.fromPolygons(a.allPolygons())
       result.properties = this.properties._merge(csg.properties)
       if (retesselate) result = result.reTesselated()
       if (canonicalize) result = result.canonicalized()
       return result
     },
     // Return a new CSG solid representing space both this solid and in the
     // solid `csg`. Neither this solid nor the solid `csg` are modified.
     //
     //     A.intersect(B)
     //
     //     +-------+
     //     |       |
     //     |   A   |
     //     |    +--+----+   =   +--+
     //     +----+--+    |       +--+
     //          |   B   |
     //          |       |
     //          +-------+
     //
     intersect: function (csg) {
       var csgs
       if (csg instanceof Array) {
         csgs = csg
       } else {
         csgs = [csg]
       }
       var result = this
       for (var i = 0; i < csgs.length; i++) {
         var islast = (i === (csgs.length - 1))
         result = result.intersectSub(csgs[i], islast, islast)
       }
       return result
     },
     intersectSub: function (csg, retesselate, canonicalize) {
       var a = new CSG.Tree(this.polygons)
       var b = new CSG.Tree(csg.polygons)
       a.invert()
       b.clipTo(a)
       b.invert()
       a.clipTo(b)
       b.clipTo(a)
       a.addPolygons(b.allPolygons())
       a.invert()
       var result = CSG.fromPolygons(a.allPolygons())
       result.properties = this.properties._merge(csg.properties)
       if (retesselate) result = result.reTesselated()
       if (canonicalize) result = result.canonicalized()
       return result
     },
     // Return a new CSG solid with solid and empty space switched. This solid is
     // not modified.
     invert: function () {
       var flippedpolygons = this.polygons.map(function (p) {
         return p.flipped()
       })
       return CSG.fromPolygons(flippedpolygons)
         // TODO: flip properties?
     },
     // Affine transformation of CSG object. Returns a new CSG object
     transform1: function (matrix4x4) {
       var newpolygons = this.polygons.map(function (p) {
         return p.transform(matrix4x4)
       })
       var result = CSG.fromPolygons(newpolygons)
       result.properties = this.properties._transform(matrix4x4)
       result.isRetesselated = this.isRetesselated
       return result
     },
     transform: function (matrix4x4) {
       var ismirror = matrix4x4.isMirroring()
       var transformedvertices = {}
       var transformedplanes = {}
       var newpolygons = this.polygons.map(function (p) {
         var newplane
         var plane = p.plane
         var planetag = plane.getTag()
         if (planetag in transformedplanes) {
           newplane = transformedplanes[planetag]
         } else {
           newplane = plane.transform(matrix4x4)
           transformedplanes[planetag] = newplane
         }
         var newvertices = p.vertices.map(function (v) {
           var newvertex
           var vertextag = v.getTag()
           if (vertextag in transformedvertices) {
             newvertex = transformedvertices[vertextag]
           } else {
             newvertex = v.transform(matrix4x4)
             transformedvertices[vertextag] = newvertex
           }
           return newvertex
         })
         if (ismirror) newvertices.reverse()
         return new CSG.Polygon(newvertices, p.shared, newplane)
       })
       var result = CSG.fromPolygons(newpolygons)
       result.properties = this.properties._transform(matrix4x4)
       result.isRetesselated = this.isRetesselated
       result.isCanonicalized = this.isCanonicalized
       return result
     },
     toString: function () {
       var result = "CSG solid:\n"
       this.polygons.map(function (p) {
         result += p.toString()
       })
       return result
     },
     // Expand the solid
     // resolution: number of points per 360 degree for the rounded corners
     expand: function (radius, resolution) {
       var result = this.expandedShell(radius, resolution, true)
       result = result.reTesselated()
       result.properties = this.properties // keep original properties
       return result
     },
     // Contract the solid
     // resolution: number of points per 360 degree for the rounded corners
     contract: function (radius, resolution) {
       var expandedshell = this.expandedShell(radius, resolution, false)
       var result = this.subtract(expandedshell)
       result = result.reTesselated()
       result.properties = this.properties // keep original properties
       return result
     },
     // cut the solid at a plane, and stretch the cross-section found along plane normal
     stretchAtPlane: function (normal, point, length) {
       var plane = CSG.Plane.fromNormalAndPoint(normal, point)
       var onb = new CSG.OrthoNormalBasis(plane)
       var crosssect = this.sectionCut(onb)
       var midpiece = crosssect.extrudeInOrthonormalBasis(onb, length)
       var piece1 = this.cutByPlane(plane)
       var piece2 = this.cutByPlane(plane.flipped())
       var result = piece1.union([midpiece, piece2.translate(plane.normal.times(length))])
       return result
     },
     // Create the expanded shell of the solid:
     // All faces are extruded to get a thickness of 2*radius
     // Cylinders are constructed around every side
     // Spheres are placed on every vertex
     // unionWithThis: if true, the resulting solid will be united with 'this' solid;
     //   the result is a true expansion of the solid
     //   If false, returns only the shell
     expandedShell: function (radius, resolution, unionWithThis) {
       var csg = this.reTesselated()
       var result
       if (unionWithThis) {
         result = csg
       } else {
         result = new CSG()
       }
       // first extrude all polygons:
       csg.polygons.map(function (polygon) {
         var extrudevector = polygon.plane.normal.unit().times(2 * radius)
         var translatedpolygon = polygon.translate(extrudevector.times(-0.5))
         var extrudedface = translatedpolygon.extrude(extrudevector)
         result = result.unionSub(extrudedface, false, false)
       })
       // Make a list of all unique vertex pairs (i.e. all sides of the solid)
       // For each vertex pair we collect the following:
       //   v1: first coordinate
       //   v2: second coordinate
       //   planenormals: array of normal vectors of all planes touching this side
       var vertexpairs = {} // map of 'vertex pair tag' to {v1, v2, planenormals}
       csg.polygons.map(function (polygon) {
         var numvertices = polygon.vertices.length
         var prevvertex = polygon.vertices[numvertices - 1]
         var prevvertextag = prevvertex.getTag()
         for (var i = 0; i < numvertices; i++) {
           var vertex = polygon.vertices[i]
           var vertextag = vertex.getTag()
           var vertextagpair
           if (vertextag < prevvertextag) {
             vertextagpair = vertextag + "-" + prevvertextag
           } else {
             vertextagpair = prevvertextag + "-" + vertextag
           }
           var obj
           if (vertextagpair in vertexpairs) {
             obj = vertexpairs[vertextagpair]
           } else {
             obj = {
               v1: prevvertex,
               v2: vertex,
               planenormals: []
             }
             vertexpairs[vertextagpair] = obj
           }
           obj.planenormals.push(polygon.plane.normal)
           prevvertextag = vertextag
           prevvertex = vertex
         }
       })
       // now construct a cylinder on every side
       // The cylinder is always an approximation of a true cylinder: it will have <resolution> polygons
       // around the sides. We will make sure though that the cylinder will have an edge at every
       // face that touches this side. This ensures that we will get a smooth fill even
       // if two edges are at, say, 10 degrees and the resolution is low.
       // Note: the result is not retesselated yet but it really should be!
       for (var vertextagpair in vertexpairs) {
         var vertexpair = vertexpairs[vertextagpair],
           startpoint = vertexpair.v1.pos,
           endpoint = vertexpair.v2.pos,
           // our x,y and z vectors:
           zbase = endpoint.minus(startpoint).unit(),
           xbase = vertexpair.planenormals[0].unit(),
           ybase = xbase.cross(zbase),
           // make a list of angles that the cylinder should traverse:
           angles = []
           // first of all equally spaced around the cylinder:
         for (var i = 0; i < resolution; i++) {
           angles.push(i * Math.PI * 2 / resolution)
         }
         // and also at every normal of all touching planes:
         for (var i = 0, iMax = vertexpair.planenormals.length; i < iMax; i++) {
           var planenormal = vertexpair.planenormals[i],
             si = ybase.dot(planenormal),
             co = xbase.dot(planenormal),
             angle = Math.atan2(si, co)
           if (angle < 0) angle += Math.PI * 2
           angles.push(angle)
           angle = Math.atan2(-si, -co)
           if (angle < 0) angle += Math.PI * 2
           angles.push(angle)
         }
         // this will result in some duplicate angles but we will get rid of those later.
         // Sort:
         angles = angles.sort(fnNumberSort)
           // Now construct the cylinder by traversing all angles:
         var numangles = angles.length,
           prevp1, prevp2,
           startfacevertices = [],
           endfacevertices = [],
           polygons = []
         for (var i = -1; i < numangles; i++) {
           var angle = angles[(i < 0) ? (i + numangles) : i],
             si = Math.sin(angle),
             co = Math.cos(angle),
             p = xbase.times(co * radius).plus(ybase.times(si * radius)),
             p1 = startpoint.plus(p),
             p2 = endpoint.plus(p),
             skip = false
           if (i >= 0) {
             if (p1.distanceTo(prevp1) < 1e-5) {
               skip = true
             }
           }
           if (!skip) {
             if (i >= 0) {
               startfacevertices.push(new CSG.Vertex(p1))
               endfacevertices.push(new CSG.Vertex(p2))
               var polygonvertices = [
                 new CSG.Vertex(prevp2),
                 new CSG.Vertex(p2),
                 new CSG.Vertex(p1),
                 new CSG.Vertex(prevp1)
               ]
               var polygon = new CSG.Polygon(polygonvertices)
               polygons.push(polygon)
             }
             prevp1 = p1
             prevp2 = p2
           }
         }
         endfacevertices.reverse()
         polygons.push(new CSG.Polygon(startfacevertices))
         polygons.push(new CSG.Polygon(endfacevertices))
         var cylinder = CSG.fromPolygons(polygons)
         result = result.unionSub(cylinder, false, false)
       }
       // make a list of all unique vertices
       // For each vertex we also collect the list of normals of the planes touching the vertices
       var vertexmap = {}
       csg.polygons.map(function (polygon) {
         polygon.vertices.map(function (vertex) {
           var vertextag = vertex.getTag()
           var obj
           if (vertextag in vertexmap) {
             obj = vertexmap[vertextag]
           } else {
             obj = {
               pos: vertex.pos,
               normals: []
             }
             vertexmap[vertextag] = obj
           }
           obj.normals.push(polygon.plane.normal)
         })
       })
       // and build spheres at each vertex
       // We will try to set the x and z axis to the normals of 2 planes
       // This will ensure that our sphere tesselation somewhat matches 2 planes
       for (var vertextag in vertexmap) {
         var vertexobj = vertexmap[vertextag]
           // use the first normal to be the x axis of our sphere:
         var xaxis = vertexobj.normals[0].unit()
           // and find a suitable z axis. We will use the normal which is most perpendicular to the x axis:
         var bestzaxis = null
         var bestzaxisorthogonality = 0
         for (var i = 1; i < vertexobj.normals.length; i++) {
           var normal = vertexobj.normals[i].unit()
           var cross = xaxis.cross(normal)
           var crosslength = cross.length()
           if (crosslength > 0.05) {
             if (crosslength > bestzaxisorthogonality) {
               bestzaxisorthogonality = crosslength
               bestzaxis = normal
             }
           }
         }
         if (!bestzaxis) {
           bestzaxis = xaxis.randomNonParallelVector()
         }
         var yaxis = xaxis.cross(bestzaxis).unit()
         var zaxis = yaxis.cross(xaxis)
         var sphere = CSG.sphere({
           center: vertexobj.pos,
           radius: radius,
           resolution: resolution,
           axes: [xaxis, yaxis, zaxis]
         })
         result = result.unionSub(sphere, false, false)
       }
       return result
     },
     canonicalized: function () {
       if (this.isCanonicalized) {
         return this
       } else {
         var factory = new CSG.fuzzyCSGFactory()
         var result = factory.getCSG(this)
         result.isCanonicalized = true
         result.isRetesselated = this.isRetesselated
         result.properties = this.properties // keep original properties
         return result
       }
     },
     reTesselated: function () {
       if (this.isRetesselated) {
         return this
       } else {
         var csg = this
         var polygonsPerPlane = {}
         var isCanonicalized = csg.isCanonicalized
         var fuzzyfactory = new CSG.fuzzyCSGFactory()
         csg.polygons.map(function (polygon) {
           var plane = polygon.plane
           var shared = polygon.shared
           if (!isCanonicalized) {
             // in order to identify to polygons having the same plane, we need to canonicalize the planes
             // We don't have to do a full canonizalization (including vertices), to save time only do the planes and the shared data:
             plane = fuzzyfactory.getPlane(plane)
             shared = fuzzyfactory.getPolygonShared(shared)
           }
           var tag = plane.getTag() + "/" + shared.getTag()
           if (!(tag in polygonsPerPlane)) {
             polygonsPerPlane[tag] = [polygon]
           } else {
             polygonsPerPlane[tag].push(polygon)
           }
         })
         var destpolygons = []
         for (var planetag in polygonsPerPlane) {
           var sourcepolygons = polygonsPerPlane[planetag]
           if (sourcepolygons.length < 2) {
             destpolygons = destpolygons.concat(sourcepolygons)
           } else {
             var retesselayedpolygons = []
             CSG.reTesselateCoplanarPolygons(sourcepolygons, retesselayedpolygons)
             destpolygons = destpolygons.concat(retesselayedpolygons)
           }
         }
         var result = CSG.fromPolygons(destpolygons)
         result.isRetesselated = true
           // result = result.canonicalized();
         result.properties = this.properties // keep original properties
         return result
       }
     },
     // returns an array of two CSG.Vector3Ds (minimum coordinates and maximum coordinates)
     getBounds: function () {
       if (!this.cachedBoundingBox) {
         var minpoint = new CSG.Vector3D(0, 0, 0)
         var maxpoint = new CSG.Vector3D(0, 0, 0)
         var polygons = this.polygons
         var numpolygons = polygons.length
         for (var i = 0; i < numpolygons; i++) {
           var polygon = polygons[i]
           var bounds = polygon.boundingBox()
           if (i === 0) {
             minpoint = bounds[0]
             maxpoint = bounds[1]
           } else {
             minpoint = minpoint.min(bounds[0])
             maxpoint = maxpoint.max(bounds[1])
           }
         }
         this.cachedBoundingBox = [minpoint, maxpoint]
       }
       return this.cachedBoundingBox
     },
     // returns true if there is a possibility that the two solids overlap
     // returns false if we can be sure that they do not overlap
     mayOverlap: function (csg) {
       if ((this.polygons.length === 0) || (csg.polygons.length === 0)) {
         return false
       } else {
         var mybounds = this.getBounds()
         var otherbounds = csg.getBounds()
         if (mybounds[1].x < otherbounds[0].x) return false
         if (mybounds[0].x > otherbounds[1].x) return false
         if (mybounds[1].y < otherbounds[0].y) return false
         if (mybounds[0].y > otherbounds[1].y) return false
         if (mybounds[1].z < otherbounds[0].z) return false
         if (mybounds[0].z > otherbounds[1].z) return false
         return true
       }
     },
     // Cut the solid by a plane. Returns the solid on the back side of the plane
     cutByPlane: function (plane) {
       if (this.polygons.length === 0) {
         return new CSG()
       }
       // Ideally we would like to do an intersection with a polygon of inifinite size
       // but this is not supported by our implementation. As a workaround, we will create
       // a cube, with one face on the plane, and a size larger enough so that the entire
       // solid fits in the cube.
       // find the max distance of any vertex to the center of the plane:
       var planecenter = plane.normal.times(plane.w)
       var maxdistance = 0
       this.polygons.map(function (polygon) {
         polygon.vertices.map(function (vertex) {
           var distance = vertex.pos.distanceToSquared(planecenter)
           if (distance > maxdistance) maxdistance = distance
         })
       })
       maxdistance = Math.sqrt(maxdistance)
       maxdistance *= 1.01 // make sure it's really larger
         // Now build a polygon on the plane, at any point farther than maxdistance from the plane center:
       var vertices = []
       var orthobasis = new CSG.OrthoNormalBasis(plane)
       vertices.push(new CSG.Vertex(orthobasis.to3D(new CSG.Vector2D(maxdistance, -maxdistance))))
       vertices.push(new CSG.Vertex(orthobasis.to3D(new CSG.Vector2D(-maxdistance, -maxdistance))))
       vertices.push(new CSG.Vertex(orthobasis.to3D(new CSG.Vector2D(-maxdistance, maxdistance))))
       vertices.push(new CSG.Vertex(orthobasis.to3D(new CSG.Vector2D(maxdistance, maxdistance))))
       var polygon = new CSG.Polygon(vertices, null, plane.flipped())
         // and extrude the polygon into a cube, backwards of the plane:
       var cube = polygon.extrude(plane.normal.times(-maxdistance))
         // Now we can do the intersection:
       var result = this.intersect(cube)
       result.properties = this.properties // keep original properties
       return result
     },
     // Connect a solid to another solid, such that two CSG.Connectors become connected
     //   myConnector: a CSG.Connector of this solid
     //   otherConnector: a CSG.Connector to which myConnector should be connected
     //   mirror: false: the 'axis' vectors of the connectors should point in the same direction
     //           true: the 'axis' vectors of the connectors should point in opposite direction
     //   normalrotation: degrees of rotation between the 'normal' vectors of the two
     //                   connectors
     connectTo: function (myConnector, otherConnector, mirror, normalrotation) {
       var matrix = myConnector.getTransformationTo(otherConnector, mirror, normalrotation)
       return this.transform(matrix)
     },
     // set the .shared property of all polygons
     // Returns a new CSG solid, the original is unmodified!
     setShared: function (shared) {
       var polygons = this.polygons.map(function (p) {
         return new CSG.Polygon(p.vertices, shared, p.plane)
       })
       var result = CSG.fromPolygons(polygons)
       result.properties = this.properties // keep original properties
       result.isRetesselated = this.isRetesselated
       result.isCanonicalized = this.isCanonicalized
       return result
     },
     setColor: function (args) {
       var newshared = CSG.Polygon.Shared.fromColor.apply(this, arguments)
       return this.setShared(newshared)
     },
     toCompactBinary: function () {
       var csg = this.canonicalized(),
         numpolygons = csg.polygons.length,
         numpolygonvertices = 0,
         numvertices = 0,
         vertexmap = {},
         vertices = [],
         numplanes = 0,
         planemap = {},
         polygonindex = 0,
         planes = [],
         shareds = [],
         sharedmap = {},
         numshared = 0
         // for (var i = 0, iMax = csg.polygons.length; i < iMax; i++) {
         //  var p = csg.polygons[i];
         //  for (var j = 0, jMax = p.length; j < jMax; j++) {
         //      ++numpolygonvertices;
         //      var vertextag = p[j].getTag();
         //      if(!(vertextag in vertexmap)) {
         //          vertexmap[vertextag] = numvertices++;
         //          vertices.push(p[j]);
         //      }
         //  }
       csg.polygons.map(function (p) {
         p.vertices.map(function (v) {
           ++numpolygonvertices
           var vertextag = v.getTag()
           if (!(vertextag in vertexmap)) {
             vertexmap[vertextag] = numvertices++
               vertices.push(v)
           }
         })
         var planetag = p.plane.getTag()
         if (!(planetag in planemap)) {
           planemap[planetag] = numplanes++
             planes.push(p.plane)
         }
         var sharedtag = p.shared.getTag()
         if (!(sharedtag in sharedmap)) {
           sharedmap[sharedtag] = numshared++
             shareds.push(p.shared)
         }
       })
       var numVerticesPerPolygon = new Uint32Array(numpolygons),
         polygonSharedIndexes = new Uint32Array(numpolygons),
         polygonVertices = new Uint32Array(numpolygonvertices),
         polygonPlaneIndexes = new Uint32Array(numpolygons),
         vertexData = new Float64Array(numvertices * 3),
         planeData = new Float64Array(numplanes * 4),
         polygonVerticesIndex = 0
       for (var polygonindex = 0; polygonindex < numpolygons; ++polygonindex) {
         var p = csg.polygons[polygonindex]
         numVerticesPerPolygon[polygonindex] = p.vertices.length
         p.vertices.map(function (v) {
           var vertextag = v.getTag()
           var vertexindex = vertexmap[vertextag]
           polygonVertices[polygonVerticesIndex++] = vertexindex
         })
         var planetag = p.plane.getTag()
         var planeindex = planemap[planetag]
         polygonPlaneIndexes[polygonindex] = planeindex
         var sharedtag = p.shared.getTag()
         var sharedindex = sharedmap[sharedtag]
         polygonSharedIndexes[polygonindex] = sharedindex
       }
       var verticesArrayIndex = 0
       vertices.map(function (v) {
         var pos = v.pos
         vertexData[verticesArrayIndex++] = pos._x
         vertexData[verticesArrayIndex++] = pos._y
         vertexData[verticesArrayIndex++] = pos._z
       })
       var planesArrayIndex = 0
       planes.map(function (p) {
         var normal = p.normal
         planeData[planesArrayIndex++] = normal._x
         planeData[planesArrayIndex++] = normal._y
         planeData[planesArrayIndex++] = normal._z
         planeData[planesArrayIndex++] = p.w
       })
       var result = {
         "class": "CSG",
         numPolygons: numpolygons,
         numVerticesPerPolygon: numVerticesPerPolygon,
         polygonPlaneIndexes: polygonPlaneIndexes,
         polygonSharedIndexes: polygonSharedIndexes,
         polygonVertices: polygonVertices,
         vertexData: vertexData,
         planeData: planeData,
         shared: shareds
       }
       return result
     },
     // For debugging
     // Creates a new solid with a tiny cube at every vertex of the source solid
     toPointCloud: function (cuberadius) {
       var csg = this.reTesselated()
       var result = new CSG()
         // make a list of all unique vertices
         // For each vertex we also collect the list of normals of the planes touching the vertices
       var vertexmap = {}
       csg.polygons.map(function (polygon) {
         polygon.vertices.map(function (vertex) {
           vertexmap[vertex.getTag()] = vertex.pos
         })
       })
       for (var vertextag in vertexmap) {
         var pos = vertexmap[vertextag]
         var cube = CSG.cube({
           center: pos,
           radius: cuberadius
         })
         result = result.unionSub(cube, false, false)
       }
       result = result.reTesselated()
       return result
     },
     // Get the transformation that transforms this CSG such that it is lying on the z=0 plane,
     // as flat as possible (i.e. the least z-height).
     // So that it is in an orientation suitable for CNC milling
     getTransformationAndInverseTransformationToFlatLying: function () {
       if (this.polygons.length === 0) {
         return new CSG.Matrix4x4() // unity
       } else {
         // get a list of unique planes in the CSG:
         var csg = this.canonicalized()
         var planemap = {}
         csg.polygons.map(function (polygon) {
           planemap[polygon.plane.getTag()] = polygon.plane
         })
         // try each plane in the CSG and find the plane that, when we align it flat onto z=0,
         // gives the least height in z-direction.
         // If two planes give the same height, pick the plane that originally had a normal closest
         // to [0,0,-1].
         var xvector = new CSG.Vector3D(1, 0, 0)
         var yvector = new CSG.Vector3D(0, 1, 0)
         var zvector = new CSG.Vector3D(0, 0, 1)
         var z0connectorx = new CSG.Connector([0, 0, 0], [0, 0, -1], xvector)
         var z0connectory = new CSG.Connector([0, 0, 0], [0, 0, -1], yvector)
         var isfirst = true
         var minheight = 0
         var maxdotz = 0
         var besttransformation, bestinversetransformation
         for (var planetag in planemap) {
           var plane = planemap[planetag]
           var pointonplane = plane.normal.times(plane.w)
           var transformation, inversetransformation
             // We need a normal vecrtor for the transformation
             // determine which is more perpendicular to the plane normal: x or y?
             // we will align this as much as possible to the x or y axis vector
           var xorthogonality = plane.normal.cross(xvector).length()
           var yorthogonality = plane.normal.cross(yvector).length()
           if (xorthogonality > yorthogonality) {
             // x is better:
             var planeconnector = new CSG.Connector(pointonplane, plane.normal, xvector)
             transformation = planeconnector.getTransformationTo(z0connectorx, false, 0)
             inversetransformation = z0connectorx.getTransformationTo(planeconnector, false, 0)
           } else {
             // y is better:
             var planeconnector = new CSG.Connector(pointonplane, plane.normal, yvector)
             transformation = planeconnector.getTransformationTo(z0connectory, false, 0)
             inversetransformation = z0connectory.getTransformationTo(planeconnector, false, 0)
           }
           var transformedcsg = csg.transform(transformation)
           var dotz = -plane.normal.dot(zvector)
           var bounds = transformedcsg.getBounds()
           var zheight = bounds[1].z - bounds[0].z
           var isbetter = isfirst
           if (!isbetter) {
             if (zheight < minheight) {
               isbetter = true
             } else if (zheight === minheight) {
               if (dotz > maxdotz) isbetter = true
             }
           }
           if (isbetter) {
             // translate the transformation around the z-axis and onto the z plane:
             var translation = new CSG.Vector3D([-0.5 * (bounds[1].x + bounds[0].x), -0.5 * (bounds[1].y + bounds[0].y), -bounds[0].z])
             transformation = transformation.multiply(CSG.Matrix4x4.translation(translation))
             inversetransformation = CSG.Matrix4x4.translation(translation.negated()).multiply(inversetransformation)
             minheight = zheight
             maxdotz = dotz
             besttransformation = transformation
             bestinversetransformation = inversetransformation
           }
           isfirst = false
         }
         return [besttransformation, bestinversetransformation]
       }
     },
     getTransformationToFlatLying: function () {
       var result = this.getTransformationAndInverseTransformationToFlatLying()
       return result[0]
     },
     lieFlat: function () {
       var transformation = this.getTransformationToFlatLying()
       return this.transform(transformation)
     },
     // project the 3D CSG onto a plane
     // This returns a 2D CAG with the 'shadow' shape of the 3D solid when projected onto the
     // plane represented by the orthonormal basis
     projectToOrthoNormalBasis: function (orthobasis) {
       var EPS = 1e-5
       var cags = []
       this.polygons.filter(function (p) {
         // only return polys in plane, others may disturb result
         return p.plane.normal.minus(orthobasis.plane.normal).lengthSquared() < EPS * EPS
       })
       .map(function (polygon) {
         var cag = polygon.projectToOrthoNormalBasis(orthobasis)
         if (cag.sides.length > 0) {
           cags.push(cag)
         }
       })
       var result = new CAG().union(cags)
       return result
     },
     sectionCut: function (orthobasis) {
       var EPS = 1e-5
       var plane1 = orthobasis.plane
       var plane2 = orthobasis.plane.flipped()
       plane1 = new CSG.Plane(plane1.normal, plane1.w)
       plane2 = new CSG.Plane(plane2.normal, plane2.w + 5 * EPS)
       var cut3d = this.cutByPlane(plane1)
       cut3d = cut3d.cutByPlane(plane2)
       return cut3d.projectToOrthoNormalBasis(orthobasis)
     },
     /*
      fixTJunctions:

      Suppose we have two polygons ACDB and EDGF:

       A-----B
       |     |
       |     E--F
       |     |  |
       C-----D--G

      Note that vertex E forms a T-junction on the side BD. In this case some STL slicers will complain
      that the solid is not watertight. This is because the watertightness check is done by checking if
      each side DE is matched by another side ED.

      This function will return a new solid with ACDB replaced by ACDEB

      Note that this can create polygons that are slightly non-convex (due to rounding errors). Therefore the result should
      not be used for further CSG operations!
      */
     fixTJunctions: function () {
       var csg = this.canonicalized()
       var sidemap = {}
       for (var polygonindex = 0; polygonindex < csg.polygons.length; polygonindex++) {
         var polygon = csg.polygons[polygonindex]
         var numvertices = polygon.vertices.length
         if (numvertices >= 3) // should be true
         {
           var vertex = polygon.vertices[0]
           var vertextag = vertex.getTag()
           for (var vertexindex = 0; vertexindex < numvertices; vertexindex++) {
             var nextvertexindex = vertexindex + 1
             if (nextvertexindex === numvertices) nextvertexindex = 0
             var nextvertex = polygon.vertices[nextvertexindex]
             var nextvertextag = nextvertex.getTag()
             var sidetag = vertextag + "/" + nextvertextag
             var reversesidetag = nextvertextag + "/" + vertextag
             if (reversesidetag in sidemap) {
               // this side matches the same side in another polygon. Remove from sidemap:
               var ar = sidemap[reversesidetag]
               ar.splice(-1, 1)
               if (ar.length === 0) {
                 delete sidemap[reversesidetag]
               }
             } else {
               var sideobj = {
                 vertex0: vertex,
                 vertex1: nextvertex,
                 polygonindex: polygonindex
               }
               if (!(sidetag in sidemap)) {
                 sidemap[sidetag] = [sideobj]
               } else {
                 sidemap[sidetag].push(sideobj)
               }
             }
             vertex = nextvertex
             vertextag = nextvertextag
           }
         }
       }
       // now sidemap contains 'unmatched' sides
       // i.e. side AB in one polygon does not have a matching side BA in another polygon
       var vertextag2sidestart = {}
       var vertextag2sideend = {}
       var sidestocheck = {}
       var sidemapisempty = true
       for (var sidetag in sidemap) {
         sidemapisempty = false
         sidestocheck[sidetag] = true
         sidemap[sidetag].map(function (sideobj) {
           var starttag = sideobj.vertex0.getTag()
           var endtag = sideobj.vertex1.getTag()
           if (starttag in vertextag2sidestart) {
             vertextag2sidestart[starttag].push(sidetag)
           } else {
             vertextag2sidestart[starttag] = [sidetag]
           }
           if (endtag in vertextag2sideend) {
             vertextag2sideend[endtag].push(sidetag)
           } else {
             vertextag2sideend[endtag] = [sidetag]
           }
         })
       }
       if (!sidemapisempty) {
         // make a copy of the polygons array, since we are going to modify it:
         var polygons = csg.polygons.slice(0)

         function addSide(vertex0, vertex1, polygonindex) {
           var starttag = vertex0.getTag()
           var endtag = vertex1.getTag()
           if (starttag === endtag) throw new Error("Assertion failed")
           var newsidetag = starttag + "/" + endtag
           var reversesidetag = endtag + "/" + starttag
           if (reversesidetag in sidemap) {
             // we have a matching reverse oriented side.
             // Instead of adding the new side, cancel out the reverse side:
             // console.log("addSide("+newsidetag+") has reverse side:");
             deleteSide(vertex1, vertex0, null)
             return null
           }
           //  console.log("addSide("+newsidetag+")");
           var newsideobj = {
             vertex0: vertex0,
             vertex1: vertex1,
             polygonindex: polygonindex
           }
           if (!(newsidetag in sidemap)) {
             sidemap[newsidetag] = [newsideobj]
           } else {
             sidemap[newsidetag].push(newsideobj)
           }
           if (starttag in vertextag2sidestart) {
             vertextag2sidestart[starttag].push(newsidetag)
           } else {
             vertextag2sidestart[starttag] = [newsidetag]
           }
           if (endtag in vertextag2sideend) {
             vertextag2sideend[endtag].push(newsidetag)
           } else {
             vertextag2sideend[endtag] = [newsidetag]
           }
           return newsidetag
         }

         function deleteSide(vertex0, vertex1, polygonindex) {
           var starttag = vertex0.getTag()
           var endtag = vertex1.getTag()
           var sidetag = starttag + "/" + endtag
             // console.log("deleteSide("+sidetag+")");
           if (!(sidetag in sidemap)) throw new Error("Assertion failed")
           var idx = -1
           var sideobjs = sidemap[sidetag]
           for (var i = 0; i < sideobjs.length; i++) {
             var sideobj = sideobjs[i]
             if (sideobj.vertex0 !== vertex0) continue
             if (sideobj.vertex1 !== vertex1) continue
             if (polygonindex !== null) {
               if (sideobj.polygonindex !== polygonindex) continue
             }
             idx = i
             break
           }
           if (idx < 0) throw new Error("Assertion failed")
           sideobjs.splice(idx, 1)
           if (sideobjs.length === 0) {
             delete sidemap[sidetag]
           }
           idx = vertextag2sidestart[starttag].indexOf(sidetag)
           if (idx < 0) throw new Error("Assertion failed")
           vertextag2sidestart[starttag].splice(idx, 1)
           if (vertextag2sidestart[starttag].length === 0) {
             delete vertextag2sidestart[starttag]
           }
           idx = vertextag2sideend[endtag].indexOf(sidetag)
           if (idx < 0) throw new Error("Assertion failed")
           vertextag2sideend[endtag].splice(idx, 1)
           if (vertextag2sideend[endtag].length === 0) {
             delete vertextag2sideend[endtag]
           }
         }
         while (true) {
           var sidemapisempty = true
           for (var sidetag in sidemap) {
             sidemapisempty = false
             sidestocheck[sidetag] = true
           }
           if (sidemapisempty) break
           var donesomething = false
           while (true) {
             var sidetagtocheck = null
             for (var sidetag in sidestocheck) {
               sidetagtocheck = sidetag
               break
             }
             if (sidetagtocheck === null) break // sidestocheck is empty, we're done!
             var donewithside = true
             if (sidetagtocheck in sidemap) {
               var sideobjs = sidemap[sidetagtocheck]
               if (sideobjs.length === 0) throw new Error("Assertion failed")
               var sideobj = sideobjs[0]
               for (var directionindex = 0; directionindex < 2; directionindex++) {
                 var startvertex = (directionindex === 0) ? sideobj.vertex0 : sideobj.vertex1
                 var endvertex = (directionindex === 0) ? sideobj.vertex1 : sideobj.vertex0
                 var startvertextag = startvertex.getTag()
                 var endvertextag = endvertex.getTag()
                 var matchingsides = []
                 if (directionindex === 0) {
                   if (startvertextag in vertextag2sideend) {
                     matchingsides = vertextag2sideend[startvertextag]
                   }
                 } else {
                   if (startvertextag in vertextag2sidestart) {
                     matchingsides = vertextag2sidestart[startvertextag]
                   }
                 }
                 for (var matchingsideindex = 0; matchingsideindex < matchingsides.length; matchingsideindex++) {
                   var matchingsidetag = matchingsides[matchingsideindex]
                   var matchingside = sidemap[matchingsidetag][0]
                   var matchingsidestartvertex = (directionindex === 0) ? matchingside.vertex0 : matchingside.vertex1
                   var matchingsideendvertex = (directionindex === 0) ? matchingside.vertex1 : matchingside.vertex0
                   var matchingsidestartvertextag = matchingsidestartvertex.getTag()
                   var matchingsideendvertextag = matchingsideendvertex.getTag()
                   if (matchingsideendvertextag !== startvertextag) throw new Error("Assertion failed")
                   if (matchingsidestartvertextag === endvertextag) {
                     // matchingside cancels sidetagtocheck
                     deleteSide(startvertex, endvertex, null)
                     deleteSide(endvertex, startvertex, null)
                     donewithside = false
                     directionindex = 2 // skip reverse direction check
                     donesomething = true
                     break
                   } else {
                     var startpos = startvertex.pos
                     var endpos = endvertex.pos
                     var checkpos = matchingsidestartvertex.pos
                     var direction = checkpos.minus(startpos)
                       // Now we need to check if endpos is on the line startpos-checkpos:
                     var t = endpos.minus(startpos).dot(direction) / direction.dot(direction)
                     if ((t > 0) && (t < 1)) {
                       var closestpoint = startpos.plus(direction.times(t))
                       var distancesquared = closestpoint.distanceToSquared(endpos)
                       if (distancesquared < 1e-10) {
                         // Yes it's a t-junction! We need to split matchingside in two:
                         var polygonindex = matchingside.polygonindex
                         var polygon = polygons[polygonindex]
                           // find the index of startvertextag in polygon:
                         var insertionvertextag = matchingside.vertex1.getTag()
                         var insertionvertextagindex = -1
                         for (var i = 0; i < polygon.vertices.length; i++) {
                           if (polygon.vertices[i].getTag() === insertionvertextag) {
                             insertionvertextagindex = i
                             break
                           }
                         }
                         if (insertionvertextagindex < 0) throw new Error("Assertion failed")
                           // split the side by inserting the vertex:
                         var newvertices = polygon.vertices.slice(0)
                         newvertices.splice(insertionvertextagindex, 0, endvertex)
                         var newpolygon = new CSG.Polygon(newvertices, polygon.shared /*polygon.plane*/ )
                         polygons[polygonindex] = newpolygon
                           // remove the original sides from our maps:
                           // deleteSide(sideobj.vertex0, sideobj.vertex1, null);
                         deleteSide(matchingside.vertex0, matchingside.vertex1, polygonindex)
                         var newsidetag1 = addSide(matchingside.vertex0, endvertex, polygonindex)
                         var newsidetag2 = addSide(endvertex, matchingside.vertex1, polygonindex)
                         if (newsidetag1 !== null) sidestocheck[newsidetag1] = true
                         if (newsidetag2 !== null) sidestocheck[newsidetag2] = true
                         donewithside = false
                         directionindex = 2 // skip reverse direction check
                         donesomething = true
                         break
                       } // if(distancesquared < 1e-10)
                     } // if( (t > 0) && (t < 1) )
                   } // if(endingstidestartvertextag === endvertextag)
                 } // for matchingsideindex
               } // for directionindex
             } // if(sidetagtocheck in sidemap)
             if (donewithside) {
               delete sidestocheck[sidetag]
             }
           }
           if (!donesomething) break
         }
         var newcsg = CSG.fromPolygons(polygons)
         newcsg.properties = csg.properties
         newcsg.isCanonicalized = true
         newcsg.isRetesselated = true
         csg = newcsg
       } // if(!sidemapisempty)
       var sidemapisempty = true
       for (var sidetag in sidemap) {
         sidemapisempty = false
         break
       }
       if (!sidemapisempty) {
         // throw new Error("!sidemapisempty");
         OpenJsCad.log("!sidemapisempty")
       }
       return csg
     },
     toTriangles: function () {
       var polygons = []
       this.polygons.forEach(function (poly) {
         var firstVertex = poly.vertices[0]
         for (var i = poly.vertices.length - 3; i >= 0; i--) {
           polygons.push(new CSG.Polygon([
               firstVertex, poly.vertices[i + 1], poly.vertices[i + 2]
             ],
             poly.shared, poly.plane))
         }
       })
       return polygons
     },
     // features: string, or array containing 1 or more strings of: 'volume', 'area'
     // more could be added here (Fourier coeff, moments)
     getFeatures: function (features) {
       if (!(features instanceof Array)) {
         features = [features]
       }
       var result = this.toTriangles().map(function (triPoly) {
           return triPoly.getTetraFeatures(features)
         })
         .reduce(function (pv, v) {
           return v.map(function (feat, i) {
             return feat + (pv === 0 ? 0 : pv[i])
           })
         }, 0)
       return (result.length === 1) ? result[0] : result
     }
   }
   // Parse an option from the options object
   // If the option is not present, return the default value
   CSG.parseOption = function (options, optionname, defaultvalue) {
     var result = defaultvalue
     if (options) {
       if (optionname in options) {
         result = options[optionname]
       }
     }
     return result
   }
   // Parse an option and force into a CSG.Vector3D. If a scalar is passed it is converted
   // into a vector with equal x,y,z
   CSG.parseOptionAs3DVector = function (options, optionname, defaultvalue) {
     var result = CSG.parseOption(options, optionname, defaultvalue)
     result = new CSG.Vector3D(result)
     return result
   }
   CSG.parseOptionAs3DVectorList = function (options, optionname, defaultvalue) {
     var result = CSG.parseOption(options, optionname, defaultvalue)
     return result.map(function (res) {
       return new CSG.Vector3D(res)
     })
   }
   // Parse an option and force into a CSG.Vector2D. If a scalar is passed it is converted
   // into a vector with equal x,y
   CSG.parseOptionAs2DVector = function (options, optionname, defaultvalue) {
     var result = CSG.parseOption(options, optionname, defaultvalue)
     result = new CSG.Vector2D(result)
     return result
   }
   CSG.parseOptionAsFloat = function (options, optionname, defaultvalue) {
     var result = CSG.parseOption(options, optionname, defaultvalue)
     if (typeof (result) === "string") {
       result = Number(result)
     }
     if (isNaN(result) || typeof (result) !== "number") {
       throw new Error("Parameter " + optionname + " should be a number")
     }
     return result
   }
   CSG.parseOptionAsInt = function (options, optionname, defaultvalue) {
     var result = CSG.parseOption(options, optionname, defaultvalue)
     result = Number(Math.floor(result))
     if (isNaN(result)) {
       throw new Error("Parameter " + optionname + " should be a number")
     }
     return result
   }
   CSG.parseOptionAsBool = function (options, optionname, defaultvalue) {
     var result = CSG.parseOption(options, optionname, defaultvalue)
     if (typeof (result) === "string") {
       if (result === "true") result = true
       else if (result === "false") result = false
       else if (result === 0) result = false
     }
     result = !!result
     return result
   }
   // Construct an axis-aligned solid cuboid.
   // Parameters:
   //   center: center of cube (default [0,0,0])
   //   radius: radius of cube (default [1,1,1]), can be specified as scalar or as 3D vector
   //
   // Example code:
   //
   //     var cube = CSG.cube({
   //       center: [0, 0, 0],
   //       radius: 1
   //     });
   CSG.cube = function (options) {
     var c, r
     options = options || {}
     if (('corner1' in options) || ('corner2' in options)) {
       if (('center' in options) || ('radius' in options)) {
         throw new Error("cube: should either give a radius and center parameter, or a corner1 and corner2 parameter")
       }
       corner1 = CSG.parseOptionAs3DVector(options, "corner1", [0, 0, 0])
       corner2 = CSG.parseOptionAs3DVector(options, "corner2", [1, 1, 1])
       c = corner1.plus(corner2).times(0.5)
       r = corner2.minus(corner1).times(0.5)
     } else {
       c = CSG.parseOptionAs3DVector(options, "center", [0, 0, 0])
       r = CSG.parseOptionAs3DVector(options, "radius", [1, 1, 1])
     }
     r = r.abs() // negative radii make no sense
     var result = CSG.fromPolygons([
       [
         [0, 4, 6, 2],
         [-1, 0, 0]
       ],
       [
         [1, 3, 7, 5],
         [+1, 0, 0]
       ],
       [
         [0, 1, 5, 4],
         [0, -1, 0]
       ],
       [
         [2, 6, 7, 3],
         [0, +1, 0]
       ],
       [
         [0, 2, 3, 1],
         [0, 0, -1]
       ],
       [
         [4, 5, 7, 6],
         [0, 0, +1]
       ]
     ].map(function (info) {
       //var normal = new CSG.Vector3D(info[1]);
       //var plane = new CSG.Plane(normal, 1);
       var vertices = info[0].map(function (i) {
         var pos = new CSG.Vector3D(
           c.x + r.x * (2 * !!(i & 1) - 1), c.y + r.y * (2 * !!(i & 2) - 1), c.z + r.z * (2 * !!(i & 4) - 1))
         return new CSG.Vertex(pos)
       })
       return new CSG.Polygon(vertices, null /* , plane */ )
     }))
     result.properties.cube = new CSG.Properties()
     result.properties.cube.center = new CSG.Vector3D(c)
       // add 6 connectors, at the centers of each face:
     result.properties.cube.facecenters = [
       new CSG.Connector(new CSG.Vector3D([r.x, 0, 0]).plus(c), [1, 0, 0], [0, 0, 1]),
       new CSG.Connector(new CSG.Vector3D([-r.x, 0, 0]).plus(c), [-1, 0, 0], [0, 0, 1]),
       new CSG.Connector(new CSG.Vector3D([0, r.y, 0]).plus(c), [0, 1, 0], [0, 0, 1]),
       new CSG.Connector(new CSG.Vector3D([0, -r.y, 0]).plus(c), [0, -1, 0], [0, 0, 1]),
       new CSG.Connector(new CSG.Vector3D([0, 0, r.z]).plus(c), [0, 0, 1], [1, 0, 0]),
       new CSG.Connector(new CSG.Vector3D([0, 0, -r.z]).plus(c), [0, 0, -1], [1, 0, 0])
     ]
     return result
   }
   // Construct a solid sphere
   //
   // Parameters:
   //   center: center of sphere (default [0,0,0])
   //   radius: radius of sphere (default 1), must be a scalar
   //   resolution: determines the number of polygons per 360 degree revolution (default 12)
   //   axes: (optional) an array with 3 vectors for the x, y and z base vectors
   //
   // Example usage:
   //
   //     var sphere = CSG.sphere({
   //       center: [0, 0, 0],
   //       radius: 2,
   //       resolution: 32,
   //     });
   CSG.sphere = function (options) {
     options = options || {}
     var center = CSG.parseOptionAs3DVector(options, "center", [0, 0, 0])
     var radius = CSG.parseOptionAsFloat(options, "radius", 1)
     var resolution = CSG.parseOptionAsInt(options, "resolution", CSG.defaultResolution3D)
     var xvector, yvector, zvector
     if ('axes' in options) {
       xvector = options.axes[0].unit().times(radius)
       yvector = options.axes[1].unit().times(radius)
       zvector = options.axes[2].unit().times(radius)
     } else {
       xvector = new CSG.Vector3D([1, 0, 0]).times(radius)
       yvector = new CSG.Vector3D([0, -1, 0]).times(radius)
       zvector = new CSG.Vector3D([0, 0, 1]).times(radius)
     }
     if (resolution < 4) resolution = 4
     var qresolution = Math.round(resolution / 4)
     var prevcylinderpoint
     var polygons = []
     for (var slice1 = 0; slice1 <= resolution; slice1++) {
       var angle = Math.PI * 2.0 * slice1 / resolution
       var cylinderpoint = xvector.times(Math.cos(angle)).plus(yvector.times(Math.sin(angle)))
       if (slice1 > 0) {
         // cylinder vertices:
         var vertices = []
         var prevcospitch, prevsinpitch
         for (var slice2 = 0; slice2 <= qresolution; slice2++) {
           var pitch = 0.5 * Math.PI * slice2 / qresolution
           var cospitch = Math.cos(pitch)
           var sinpitch = Math.sin(pitch)
           if (slice2 > 0) {
             vertices = []
             vertices.push(new CSG.Vertex(center.plus(prevcylinderpoint.times(prevcospitch).minus(zvector.times(prevsinpitch)))))
             vertices.push(new CSG.Vertex(center.plus(cylinderpoint.times(prevcospitch).minus(zvector.times(prevsinpitch)))))
             if (slice2 < qresolution) {
               vertices.push(new CSG.Vertex(center.plus(cylinderpoint.times(cospitch).minus(zvector.times(sinpitch)))))
             }
             vertices.push(new CSG.Vertex(center.plus(prevcylinderpoint.times(cospitch).minus(zvector.times(sinpitch)))))
             polygons.push(new CSG.Polygon(vertices))
             vertices = []
             vertices.push(new CSG.Vertex(center.plus(prevcylinderpoint.times(prevcospitch).plus(zvector.times(prevsinpitch)))))
             vertices.push(new CSG.Vertex(center.plus(cylinderpoint.times(prevcospitch).plus(zvector.times(prevsinpitch)))))
             if (slice2 < qresolution) {
               vertices.push(new CSG.Vertex(center.plus(cylinderpoint.times(cospitch).plus(zvector.times(sinpitch)))))
             }
             vertices.push(new CSG.Vertex(center.plus(prevcylinderpoint.times(cospitch).plus(zvector.times(sinpitch)))))
             vertices.reverse()
             polygons.push(new CSG.Polygon(vertices))
           }
           prevcospitch = cospitch
           prevsinpitch = sinpitch
         }
       }
       prevcylinderpoint = cylinderpoint
     }
     var result = CSG.fromPolygons(polygons)
     result.properties.sphere = new CSG.Properties()
     result.properties.sphere.center = new CSG.Vector3D(center)
     result.properties.sphere.facepoint = center.plus(xvector)
     return result
   }
   // Construct a solid cylinder.
   //
   // Parameters:
   //   start: start point of cylinder (default [0, -1, 0])
   //   end: end point of cylinder (default [0, 1, 0])
   //   radius: radius of cylinder (default 1), must be a scalar
   //   resolution: determines the number of polygons per 360 degree revolution (default 12)
   //
   // Example usage:
   //
   //     var cylinder = CSG.cylinder({
   //       start: [0, -1, 0],
   //       end: [0, 1, 0],
   //       radius: 1,
   //       resolution: 16
   //     });
   CSG.cylinder = function (options) {
     var s = CSG.parseOptionAs3DVector(options, "start", [0, -1, 0])
     var e = CSG.parseOptionAs3DVector(options, "end", [0, 1, 0])
     var r = CSG.parseOptionAsFloat(options, "radius", 1)
     var rEnd = CSG.parseOptionAsFloat(options, "radiusEnd", r)
     var rStart = CSG.parseOptionAsFloat(options, "radiusStart", r)
     var alpha = CSG.parseOptionAsFloat(options, "sectorAngle", 360)
     alpha = alpha > 360 ? alpha % 360 : alpha
     if ((rEnd < 0) || (rStart < 0)) {
       throw new Error("Radius should be non-negative")
     }
     if ((rEnd === 0) && (rStart === 0)) {
       throw new Error("Either radiusStart or radiusEnd should be positive")
     }
     var slices = CSG.parseOptionAsInt(options, "resolution", CSG.defaultResolution2D)
     var ray = e.minus(s)
     var axisZ = ray.unit() //, isY = (Math.abs(axisZ.y) > 0.5);
     var axisX = axisZ.randomNonParallelVector().unit()
       //  var axisX = new CSG.Vector3D(isY, !isY, 0).cross(axisZ).unit();
     var axisY = axisX.cross(axisZ).unit()
     var start = new CSG.Vertex(s)
     var end = new CSG.Vertex(e)
     var polygons = []

     function point(stack, slice, radius) {
       var angle = slice * Math.PI * alpha / 180
       var out = axisX.times(Math.cos(angle)).plus(axisY.times(Math.sin(angle)))
       var pos = s.plus(ray.times(stack)).plus(out.times(radius))
       return new CSG.Vertex(pos)
     }
     if (alpha > 0) {
       for (var i = 0; i < slices; i++) {
         var t0 = i / slices,
           t1 = (i + 1) / slices
         if (rEnd === rStart) {
           polygons.push(new CSG.Polygon([start, point(0, t0, rEnd), point(0, t1, rEnd)]))
           polygons.push(new CSG.Polygon([point(0, t1, rEnd), point(0, t0, rEnd), point(1, t0, rEnd), point(1, t1, rEnd)]))
           polygons.push(new CSG.Polygon([end, point(1, t1, rEnd), point(1, t0, rEnd)]))
         } else {
           if (rStart > 0) {
             polygons.push(new CSG.Polygon([start, point(0, t0, rStart), point(0, t1, rStart)]))
             polygons.push(new CSG.Polygon([point(0, t0, rStart), point(1, t0, rEnd), point(0, t1, rStart)]))
           }
           if (rEnd > 0) {
             polygons.push(new CSG.Polygon([end, point(1, t1, rEnd), point(1, t0, rEnd)]))
             polygons.push(new CSG.Polygon([point(1, t0, rEnd), point(1, t1, rEnd), point(0, t1, rStart)]))
           }
         }
       }
       if (alpha < 360) {
         polygons.push(new CSG.Polygon([start, end, point(0, 0, rStart)]))
         polygons.push(new CSG.Polygon([point(0, 0, rStart), end, point(1, 0, rEnd)]))
         polygons.push(new CSG.Polygon([start, point(0, 1, rStart), end]))
         polygons.push(new CSG.Polygon([point(0, 1, rStart), point(1, 1, rEnd), end]))
       }
     }
     var result = CSG.fromPolygons(polygons)
     result.properties.cylinder = new CSG.Properties()
     result.properties.cylinder.start = new CSG.Connector(s, axisZ.negated(), axisX)
     result.properties.cylinder.end = new CSG.Connector(e, axisZ, axisX)
     var cylCenter = s.plus(ray.times(0.5))
     var fptVec = axisX.rotate(s, axisZ, -alpha / 2).times((rStart + rEnd) / 2)
     var fptVec90 = fptVec.cross(axisZ)
       // note this one is NOT a face normal for a cone. - It's horizontal from cyl perspective
     result.properties.cylinder.facepointH = new CSG.Connector(cylCenter.plus(fptVec), fptVec, axisZ)
     result.properties.cylinder.facepointH90 = new CSG.Connector(cylCenter.plus(fptVec90), fptVec90, axisZ)
     return result
   }
   // Like a cylinder, but with rounded ends instead of flat
   //
   // Parameters:
   //   start: start point of cylinder (default [0, -1, 0])
   //   end: end point of cylinder (default [0, 1, 0])
   //   radius: radius of cylinder (default 1), must be a scalar
   //   resolution: determines the number of polygons per 360 degree revolution (default 12)
   //   normal: a vector determining the starting angle for tesselation. Should be non-parallel to start.minus(end)
   //
   // Example usage:
   //
   //     var cylinder = CSG.roundedCylinder({
   //       start: [0, -1, 0],
   //       end: [0, 1, 0],
   //       radius: 1,
   //       resolution: 16
   //     });
   CSG.roundedCylinder = function (options) {
     var p1 = CSG.parseOptionAs3DVector(options, "start", [0, -1, 0])
     var p2 = CSG.parseOptionAs3DVector(options, "end", [0, 1, 0])
     var radius = CSG.parseOptionAsFloat(options, "radius", 1)
     var direction = p2.minus(p1)
     var defaultnormal
     if (Math.abs(direction.x) > Math.abs(direction.y)) {
       defaultnormal = new CSG.Vector3D(0, 1, 0)
     } else {
       defaultnormal = new CSG.Vector3D(1, 0, 0)
     }
     var normal = CSG.parseOptionAs3DVector(options, "normal", defaultnormal)
     var resolution = CSG.parseOptionAsInt(options, "resolution", CSG.defaultResolution3D)
     if (resolution < 4) resolution = 4
     var polygons = []
     var qresolution = Math.floor(0.25 * resolution)
     var length = direction.length()
     if (length < 1e-10) {
       return CSG.sphere({
         center: p1,
         radius: radius,
         resolution: resolution
       })
     }
     var zvector = direction.unit().times(radius)
     var xvector = zvector.cross(normal).unit().times(radius)
     var yvector = xvector.cross(zvector).unit().times(radius)
     var prevcylinderpoint
     for (var slice1 = 0; slice1 <= resolution; slice1++) {
       var angle = Math.PI * 2.0 * slice1 / resolution
       var cylinderpoint = xvector.times(Math.cos(angle)).plus(yvector.times(Math.sin(angle)))
       if (slice1 > 0) {
         // cylinder vertices:
         var vertices = []
         vertices.push(new CSG.Vertex(p1.plus(cylinderpoint)))
         vertices.push(new CSG.Vertex(p1.plus(prevcylinderpoint)))
         vertices.push(new CSG.Vertex(p2.plus(prevcylinderpoint)))
         vertices.push(new CSG.Vertex(p2.plus(cylinderpoint)))
         polygons.push(new CSG.Polygon(vertices))
         var prevcospitch, prevsinpitch
         for (var slice2 = 0; slice2 <= qresolution; slice2++) {
           var pitch = 0.5 * Math.PI * slice2 / qresolution
             //var pitch = Math.asin(slice2/qresolution);
           var cospitch = Math.cos(pitch)
           var sinpitch = Math.sin(pitch)
           if (slice2 > 0) {
             vertices = []
             vertices.push(new CSG.Vertex(p1.plus(prevcylinderpoint.times(prevcospitch).minus(zvector.times(prevsinpitch)))))
             vertices.push(new CSG.Vertex(p1.plus(cylinderpoint.times(prevcospitch).minus(zvector.times(prevsinpitch)))))
             if (slice2 < qresolution) {
               vertices.push(new CSG.Vertex(p1.plus(cylinderpoint.times(cospitch).minus(zvector.times(sinpitch)))))
             }
             vertices.push(new CSG.Vertex(p1.plus(prevcylinderpoint.times(cospitch).minus(zvector.times(sinpitch)))))
             polygons.push(new CSG.Polygon(vertices))
             vertices = []
             vertices.push(new CSG.Vertex(p2.plus(prevcylinderpoint.times(prevcospitch).plus(zvector.times(prevsinpitch)))))
             vertices.push(new CSG.Vertex(p2.plus(cylinderpoint.times(prevcospitch).plus(zvector.times(prevsinpitch)))))
             if (slice2 < qresolution) {
               vertices.push(new CSG.Vertex(p2.plus(cylinderpoint.times(cospitch).plus(zvector.times(sinpitch)))))
             }
             vertices.push(new CSG.Vertex(p2.plus(prevcylinderpoint.times(cospitch).plus(zvector.times(sinpitch)))))
             vertices.reverse()
             polygons.push(new CSG.Polygon(vertices))
           }
           prevcospitch = cospitch
           prevsinpitch = sinpitch
         }
       }
       prevcylinderpoint = cylinderpoint
     }
     var result = CSG.fromPolygons(polygons)
     var ray = zvector.unit()
     var axisX = xvector.unit()
     result.properties.roundedCylinder = new CSG.Properties()
     result.properties.roundedCylinder.start = new CSG.Connector(p1, ray.negated(), axisX)
     result.properties.roundedCylinder.end = new CSG.Connector(p2, ray, axisX)
     result.properties.roundedCylinder.facepoint = p1.plus(xvector)
     return result
   }
   // Construct an axis-aligned solid rounded cuboid.
   // Parameters:
   //   center: center of cube (default [0,0,0])
   //   radius: radius of cube (default [1,1,1]), can be specified as scalar or as 3D vector
   //   roundradius: radius of rounded corners (default 0.2), must be a scalar
   //   resolution: determines the number of polygons per 360 degree revolution (default 8)
   //
   // Example code:
   //
   //     var cube = CSG.roundedCube({
   //       center: [0, 0, 0],
   //       radius: 1,
   //       roundradius: 0.2,
   //       resolution: 8,
   //     });
   CSG.roundedCube = function (options) {
     var EPS = 1e-5
     var minRR = 1e-2 // minroundradius 1e-3 gives rounding errors already
     var center, cuberadius
     options = options || {}
     if (('corner1' in options) || ('corner2' in options)) {
       if (('center' in options) || ('radius' in options)) {
         throw new Error("roundedCube: should either give a radius and center parameter, or a corner1 and corner2 parameter")
       }
       corner1 = CSG.parseOptionAs3DVector(options, "corner1", [0, 0, 0])
       corner2 = CSG.parseOptionAs3DVector(options, "corner2", [1, 1, 1])
       center = corner1.plus(corner2).times(0.5)
       cuberadius = corner2.minus(corner1).times(0.5)
     } else {
       center = CSG.parseOptionAs3DVector(options, "center", [0, 0, 0])
       cuberadius = CSG.parseOptionAs3DVector(options, "radius", [1, 1, 1])
     }
     cuberadius = cuberadius.abs() // negative radii make no sense
     var resolution = CSG.parseOptionAsInt(options, "resolution", CSG.defaultResolution3D)
     if (resolution < 4) resolution = 4
     if (resolution % 2 === 1 && resolution < 8) resolution = 8 // avoid ugly
     var roundradius = CSG.parseOptionAs3DVector(options, "roundradius", [0.2, 0.2, 0.2])
       // slight hack for now - total radius stays ok
     roundradius = CSG.Vector3D.Create(Math.max(roundradius.x, minRR), Math.max(roundradius.y, minRR), Math.max(roundradius.z, minRR))
     var innerradius = cuberadius.minus(roundradius)
     if (innerradius.x < 0 || innerradius.y < 0 || innerradius.z < 0) {
       throw ('roundradius <= radius!')
     }
     var res = CSG.sphere({
       radius: 1,
       resolution: resolution
     })
     res = res.scale(roundradius)
     innerradius.x > EPS && (res = res.stretchAtPlane([1, 0, 0], [0, 0, 0], 2 * innerradius.x))
     innerradius.y > EPS && (res = res.stretchAtPlane([0, 1, 0], [0, 0, 0], 2 * innerradius.y))
     innerradius.z > EPS && (res = res.stretchAtPlane([0, 0, 1], [0, 0, 0], 2 * innerradius.z))
     res = res.translate([-innerradius.x + center.x, -innerradius.y + center.y, -innerradius.z + center.z])
     res = res.reTesselated()
     res.properties.roundedCube = new CSG.Properties()
     res.properties.roundedCube.center = new CSG.Vertex(center)
     res.properties.roundedCube.facecenters = [
       new CSG.Connector(new CSG.Vector3D([cuberadius.x, 0, 0]).plus(center), [1, 0, 0], [0, 0, 1]),
       new CSG.Connector(new CSG.Vector3D([-cuberadius.x, 0, 0]).plus(center), [-1, 0, 0], [0, 0, 1]),
       new CSG.Connector(new CSG.Vector3D([0, cuberadius.y, 0]).plus(center), [0, 1, 0], [0, 0, 1]),
       new CSG.Connector(new CSG.Vector3D([0, -cuberadius.y, 0]).plus(center), [0, -1, 0], [0, 0, 1]),
       new CSG.Connector(new CSG.Vector3D([0, 0, cuberadius.z]).plus(center), [0, 0, 1], [1, 0, 0]),
       new CSG.Connector(new CSG.Vector3D([0, 0, -cuberadius.z]).plus(center), [0, 0, -1], [1, 0, 0])
     ]
     return res
   }
   /**
    * polyhedron accepts openscad style arguments. I.e. define face vertices clockwise looking from outside
    */
   CSG.polyhedron = function (options) {
     options = options || {}
     if (('points' in options) !== ('faces' in options)) {
       throw new Error("polyhedron needs 'points' and 'faces' arrays")
     }
     var vertices = CSG.parseOptionAs3DVectorList(options, "points", [
         [1, 1, 0],
         [1, -1, 0],
         [-1, -1, 0],
         [-1, 1, 0],
         [0, 0, 1]
       ])
       .map(function (pt) {
         return new CSG.Vertex(pt)
       })
     var faces = CSG.parseOption(options, "faces", [
       [0, 1, 4],
       [1, 2, 4],
       [2, 3, 4],
       [3, 0, 4],
       [1, 0, 3],
       [2, 1, 3]
     ])
     // openscad convention defines inward normals - so we have to invert here
     faces.forEach(function (face) {
       face.reverse()
     })
     var polygons = faces.map(function (face) {
       return new CSG.Polygon(face.map(function (idx) {
         return vertices[idx]
       }))
     })
     // TODO: facecenters as connectors? probably overkill. Maybe centroid
     // the re-tesselation here happens because it's so easy for a user to
     // create parametrized polyhedrons that end up with 1-2 dimensional polygons.
     // These will create infinite loops at CSG.Tree()
     return CSG.fromPolygons(polygons).reTesselated()
   }
   CSG.IsFloat = function (n) {
     return (!isNaN(n)) || (n === Infinity) || (n === -Infinity)
   }
   // solve 2x2 linear equation:
   // [ab][x] = [u]
   // [cd][y]   [v]
   CSG.solve2Linear = function (a, b, c, d, u, v) {
     var det = a * d - b * c
     var invdet = 1.0 / det
     var x = u * d - b * v
     var y = -u * c + a * v
     x *= invdet
     y *= invdet
     return [x, y]
   }
   // # class Vector3D
   // Represents a 3D vector.
   //
   // Example usage:
   //
   //     new CSG.Vector3D(1, 2, 3);
   //     new CSG.Vector3D([1, 2, 3]);
   //     new CSG.Vector3D({ x: 1, y: 2, z: 3 });
   //     new CSG.Vector3D(1, 2); // assumes z=0
   //     new CSG.Vector3D([1, 2]); // assumes z=0
   CSG.Vector3D = function (x, y, z) {
     if (arguments.length === 3) {
       this._x = parseFloat(x)
       this._y = parseFloat(y)
       this._z = parseFloat(z)
     } else if (arguments.length === 2) {
       this._x = parseFloat(x)
       this._y = parseFloat(y)
       this._z = 0
     } else {
       var ok = true
       if (arguments.length === 1) {
         if (typeof (x) === "object") {
           if (x instanceof CSG.Vector3D) {
             this._x = x._x
             this._y = x._y
             this._z = x._z
           } else if (x instanceof CSG.Vector2D) {
             this._x = x._x
             this._y = x._y
             this._z = 0
           } else if (x instanceof Array) {
             if ((x.length < 2) || (x.length > 3)) {
               ok = false
             } else {
               this._x = parseFloat(x[0])
               this._y = parseFloat(x[1])
               if (x.length === 3) {
                 this._z = parseFloat(x[2])
               } else {
                 this._z = 0
               }
             }
           } else if (('x' in x) && ('y' in x)) {
             this._x = parseFloat(x.x)
             this._y = parseFloat(x.y)
             if ('z' in x) {
               this._z = parseFloat(x.z)
             } else {
               this._z = 0
             }
           } else ok = false
         } else {
           var v = parseFloat(x)
           this._x = v
           this._y = v
           this._z = v
         }
       } else ok = false
       if (ok) {
         if ((!CSG.IsFloat(this._x)) || (!CSG.IsFloat(this._y)) || (!CSG.IsFloat(this._z))) ok = false
       }
       if (!ok) {
         throw new Error("wrong arguments")
       }
     }
   }
   // This does the same as new CSG.Vector3D(x,y,z) but it doesn't go through the constructor
   // and the parameters are not validated. Is much faster.
   CSG.Vector3D.Create = function (x, y, z) {
     var result = Object.create(CSG.Vector3D.prototype)
     result._x = x
     result._y = y
     result._z = z
     return result
   }
   CSG.Vector3D.prototype = {
     get x() {
       return this._x
     },
     get y() {
       return this._y
     },
     get z() {
       return this._z
     },
     set x(v) {
       throw new Error("Vector3D is immutable")
     },
     set y(v) {
       throw new Error("Vector3D is immutable")
     },
     set z(v) {
       throw new Error("Vector3D is immutable")
     },
     clone: function () {
       return CSG.Vector3D.Create(this._x, this._y, this._z)
     },
     negated: function () {
       return CSG.Vector3D.Create(-this._x, -this._y, -this._z)
     },
     abs: function () {
       return CSG.Vector3D.Create(Math.abs(this._x), Math.abs(this._y), Math.abs(this._z))
     },
     plus: function (a) {
       return CSG.Vector3D.Create(this._x + a._x, this._y + a._y, this._z + a._z)
     },
     minus: function (a) {
       return CSG.Vector3D.Create(this._x - a._x, this._y - a._y, this._z - a._z)
     },
     times: function (a) {
       return CSG.Vector3D.Create(this._x * a, this._y * a, this._z * a)
     },
     dividedBy: function (a) {
       return CSG.Vector3D.Create(this._x / a, this._y / a, this._z / a)
     },
     dot: function (a) {
       return this._x * a._x + this._y * a._y + this._z * a._z
     },
     lerp: function (a, t) {
       return this.plus(a.minus(this).times(t))
     },
     lengthSquared: function () {
       return this.dot(this)
     },
     length: function () {
       return Math.sqrt(this.lengthSquared())
     },
     unit: function () {
       return this.dividedBy(this.length())
     },
     cross: function (a) {
       return CSG.Vector3D.Create(
         this._y * a._z - this._z * a._y, this._z * a._x - this._x * a._z, this._x * a._y - this._y * a._x)
     },
     distanceTo: function (a) {
       return this.minus(a).length()
     },
     distanceToSquared: function (a) {
       return this.minus(a).lengthSquared()
     },
     equals: function (a) {
       return (this._x === a._x) && (this._y === a._y) && (this._z === a._z)
     },
     // Right multiply by a 4x4 matrix (the vector is interpreted as a row vector)
     // Returns a new CSG.Vector3D
     multiply4x4: function (matrix4x4) {
       return matrix4x4.leftMultiply1x3Vector(this)
     },
     transform: function (matrix4x4) {
       return matrix4x4.leftMultiply1x3Vector(this)
     },
     toString: function () {
       return "(" + this._x.toFixed(2) + ", " + this._y.toFixed(2) + ", " + this._z.toFixed(2) + ")"
     },
     // find a vector that is somewhat perpendicular to this one
     randomNonParallelVector: function () {
       var abs = this.abs()
       if ((abs._x <= abs._y) && (abs._x <= abs._z)) {
         return CSG.Vector3D.Create(1, 0, 0)
       } else if ((abs._y <= abs._x) && (abs._y <= abs._z)) {
         return CSG.Vector3D.Create(0, 1, 0)
       } else {
         return CSG.Vector3D.Create(0, 0, 1)
       }
     },
     min: function (p) {
       return CSG.Vector3D.Create(
         Math.min(this._x, p._x), Math.min(this._y, p._y), Math.min(this._z, p._z))
     },
     max: function (p) {
       return CSG.Vector3D.Create(
         Math.max(this._x, p._x), Math.max(this._y, p._y), Math.max(this._z, p._z))
     }
   }
   // # class Vertex
   // Represents a vertex of a polygon. Use your own vertex class instead of this
   // one to provide additional features like texture coordinates and vertex
   // colors. Custom vertex classes need to provide a `pos` property
   // `flipped()`, and `interpolate()` methods that behave analogous to the ones
   // defined by `CSG.Vertex`.
   CSG.Vertex = function (pos) {
     this.pos = pos
   }
   // create from an untyped object with identical property names:
   CSG.Vertex.fromObject = function (obj) {
     var pos = new CSG.Vector3D(obj.pos)
     return new CSG.Vertex(pos)
   }
   CSG.Vertex.prototype = {
     // Return a vertex with all orientation-specific data (e.g. vertex normal) flipped. Called when the
     // orientation of a polygon is flipped.
     flipped: function () {
       return this
     },
     getTag: function () {
       var result = this.tag
       if (!result) {
         result = CSG.getTag()
         this.tag = result
       }
       return result
     },
     // Create a new vertex between this vertex and `other` by linearly
     // interpolating all properties using a parameter of `t`. Subclasses should
     // override this to interpolate additional properties.
     interpolate: function (other, t) {
       var newpos = this.pos.lerp(other.pos, t)
       return new CSG.Vertex(newpos)
     },
     // Affine transformation of vertex. Returns a new CSG.Vertex
     transform: function (matrix4x4) {
       var newpos = this.pos.multiply4x4(matrix4x4)
       return new CSG.Vertex(newpos)
     },
     toString: function () {
       return this.pos.toString()
     }
   }
   // # class Plane
   // Represents a plane in 3D space.
   CSG.Plane = function (normal, w) {
     this.normal = normal
     this.w = w
   }
   // create from an untyped object with identical property names:
   CSG.Plane.fromObject = function (obj) {
     var normal = new CSG.Vector3D(obj.normal)
     var w = parseFloat(obj.w)
     return new CSG.Plane(normal, w)
   }
   // `CSG.Plane.EPSILON` is the tolerance used by `splitPolygon()` to decide if a
   // point is on the plane.
   CSG.Plane.EPSILON = 1e-5
   CSG.Plane.fromVector3Ds = function (a, b, c) {
     var n = b.minus(a).cross(c.minus(a)).unit()
     return new CSG.Plane(n, n.dot(a))
   }
   // like fromVector3Ds, but allow the vectors to be on one point or one line
   // in such a case a random plane through the given points is constructed
   CSG.Plane.anyPlaneFromVector3Ds = function (a, b, c) {
     var v1 = b.minus(a)
     var v2 = c.minus(a)
     if (v1.length() < 1e-5) {
       v1 = v2.randomNonParallelVector()
     }
     if (v2.length() < 1e-5) {
       v2 = v1.randomNonParallelVector()
     }
     var normal = v1.cross(v2)
     if (normal.length() < 1e-5) {
       // this would mean that v1 === v2.negated()
       v2 = v1.randomNonParallelVector()
       normal = v1.cross(v2)
     }
     normal = normal.unit()
     return new CSG.Plane(normal, normal.dot(a))
   }
   CSG.Plane.fromPoints = function (a, b, c) {
     a = new CSG.Vector3D(a)
     b = new CSG.Vector3D(b)
     c = new CSG.Vector3D(c)
     return CSG.Plane.fromVector3Ds(a, b, c)
   }
   CSG.Plane.fromNormalAndPoint = function (normal, point) {
     normal = new CSG.Vector3D(normal)
     point = new CSG.Vector3D(point)
     normal = normal.unit()
     var w = point.dot(normal)
     return new CSG.Plane(normal, w)
   }
   CSG.Plane.prototype = {
     flipped: function () {
       return new CSG.Plane(this.normal.negated(), -this.w)
     },
     getTag: function () {
       var result = this.tag
       if (!result) {
         result = CSG.getTag()
         this.tag = result
       }
       return result
     },
     equals: function (n) {
       return this.normal.equals(n.normal) && this.w === n.w
     },
     transform: function (matrix4x4) {
       var ismirror = matrix4x4.isMirroring()
         // get two vectors in the plane:
       var r = this.normal.randomNonParallelVector()
       var u = this.normal.cross(r)
       var v = this.normal.cross(u)
         // get 3 points in the plane:
       var point1 = this.normal.times(this.w)
       var point2 = point1.plus(u)
       var point3 = point1.plus(v)
         // transform the points:
       point1 = point1.multiply4x4(matrix4x4)
       point2 = point2.multiply4x4(matrix4x4)
       point3 = point3.multiply4x4(matrix4x4)
         // and create a new plane from the transformed points:
       var newplane = CSG.Plane.fromVector3Ds(point1, point2, point3)
       if (ismirror) {
         // the transform is mirroring
         // We should mirror the plane:
         newplane = newplane.flipped()
       }
       return newplane
     },
     // Returns object:
     // .type:
     //   0: coplanar-front
     //   1: coplanar-back
     //   2: front
     //   3: back
     //   4: spanning
     // In case the polygon is spanning, returns:
     // .front: a CSG.Polygon of the front part
     // .back: a CSG.Polygon of the back part
     splitPolygon: function (polygon) {
       var result = {
           type: null,
           front: null,
           back: null
         }
         // cache in local vars (speedup):
       var planenormal = this.normal
       var vertices = polygon.vertices
       var numvertices = vertices.length
       if (polygon.plane.equals(this)) {
         result.type = 0
       } else {
         var EPS = CSG.Plane.EPSILON
         var thisw = this.w
         var hasfront = false
         var hasback = false
         var vertexIsBack = []
         var MINEPS = -EPS
         for (var i = 0; i < numvertices; i++) {
           var t = planenormal.dot(vertices[i].pos) - thisw
           var isback = (t < 0)
           vertexIsBack.push(isback)
           if (t > EPS) hasfront = true
           if (t < MINEPS) hasback = true
         }
         if ((!hasfront) && (!hasback)) {
           // all points coplanar
           var t = planenormal.dot(polygon.plane.normal)
           result.type = (t >= 0) ? 0 : 1
         } else if (!hasback) {
           result.type = 2
         } else if (!hasfront) {
           result.type = 3
         } else {
           // spanning
           result.type = 4
           var frontvertices = [],
             backvertices = []
           var isback = vertexIsBack[0]
           for (var vertexindex = 0; vertexindex < numvertices; vertexindex++) {
             var vertex = vertices[vertexindex]
             var nextvertexindex = vertexindex + 1
             if (nextvertexindex >= numvertices) nextvertexindex = 0
             var nextisback = vertexIsBack[nextvertexindex]
             if (isback === nextisback) {
               // line segment is on one side of the plane:
               if (isback) {
                 backvertices.push(vertex)
               } else {
                 frontvertices.push(vertex)
               }
             } else {
               // line segment intersects plane:
               var point = vertex.pos
               var nextpoint = vertices[nextvertexindex].pos
               var intersectionpoint = this.splitLineBetweenPoints(point, nextpoint)
               var intersectionvertex = new CSG.Vertex(intersectionpoint)
               if (isback) {
                 backvertices.push(vertex)
                 backvertices.push(intersectionvertex)
                 frontvertices.push(intersectionvertex)
               } else {
                 frontvertices.push(vertex)
                 frontvertices.push(intersectionvertex)
                 backvertices.push(intersectionvertex)
               }
             }
             isback = nextisback
           } // for vertexindex
           // remove duplicate vertices:
           var EPS_SQUARED = CSG.Plane.EPSILON * CSG.Plane.EPSILON
           if (backvertices.length >= 3) {
             var prevvertex = backvertices[backvertices.length - 1]
             for (var vertexindex = 0; vertexindex < backvertices.length; vertexindex++) {
               var vertex = backvertices[vertexindex]
               if (vertex.pos.distanceToSquared(prevvertex.pos) < EPS_SQUARED) {
                 backvertices.splice(vertexindex, 1)
                 vertexindex--
               }
               prevvertex = vertex
             }
           }
           if (frontvertices.length >= 3) {
             var prevvertex = frontvertices[frontvertices.length - 1]
             for (var vertexindex = 0; vertexindex < frontvertices.length; vertexindex++) {
               var vertex = frontvertices[vertexindex]
               if (vertex.pos.distanceToSquared(prevvertex.pos) < EPS_SQUARED) {
                 frontvertices.splice(vertexindex, 1)
                 vertexindex--
               }
               prevvertex = vertex
             }
           }
           if (frontvertices.length >= 3) {
             result.front = new CSG.Polygon(frontvertices, polygon.shared, polygon.plane)
           }
           if (backvertices.length >= 3) {
             result.back = new CSG.Polygon(backvertices, polygon.shared, polygon.plane)
           }
         }
       }
       return result
     },
     // robust splitting of a line by a plane
     // will work even if the line is parallel to the plane
     splitLineBetweenPoints: function (p1, p2) {
       var direction = p2.minus(p1)
       var labda = (this.w - this.normal.dot(p1)) / this.normal.dot(direction)
       if (isNaN(labda)) labda = 0
       if (labda > 1) labda = 1
       if (labda < 0) labda = 0
       var result = p1.plus(direction.times(labda))
       return result
     },
     // returns CSG.Vector3D
     intersectWithLine: function (line3d) {
       return line3d.intersectWithPlane(this)
     },
     // intersection of two planes
     intersectWithPlane: function (plane) {
       return CSG.Line3D.fromPlanes(this, plane)
     },
     signedDistanceToPoint: function (point) {
       var t = this.normal.dot(point) - this.w
       return t
     },
     toString: function () {
       return "[normal: " + this.normal.toString() + ", w: " + this.w + "]"
     },
     mirrorPoint: function (point3d) {
       var distance = this.signedDistanceToPoint(point3d)
       var mirrored = point3d.minus(this.normal.times(distance * 2.0))
       return mirrored
     }
   }
   // # class Polygon
   // Represents a convex polygon. The vertices used to initialize a polygon must
   // be coplanar and form a convex loop. They do not have to be `CSG.Vertex`
   // instances but they must behave similarly (duck typing can be used for
   // customization).
   //
   // Each convex polygon has a `shared` property, which is shared between all
   // polygons that are clones of each other or were split from the same polygon.
   // This can be used to define per-polygon properties (such as surface color).
   //
   // The plane of the polygon is calculated from the vertex coordinates
   // To avoid unnecessary recalculation, the plane can alternatively be
   // passed as the third argument
   CSG.Polygon = function (vertices, shared, plane) {
     this.vertices = vertices
     if (!shared) shared = CSG.Polygon.defaultShared
     this.shared = shared
       //var numvertices = vertices.length;
     if (arguments.length >= 3) {
       this.plane = plane
     } else {
       this.plane = CSG.Plane.fromVector3Ds(vertices[0].pos, vertices[1].pos, vertices[2].pos)
     }
     if (_CSGDEBUG) {
       //this.checkIfConvex()
     }
   }
   // create from an untyped object with identical property names:
   CSG.Polygon.fromObject = function (obj) {
     var vertices = obj.vertices.map(function (v) {
       return CSG.Vertex.fromObject(v)
     })
     var shared = CSG.Polygon.Shared.fromObject(obj.shared)
     var plane = CSG.Plane.fromObject(obj.plane)
     return new CSG.Polygon(vertices, shared, plane)
   }
   CSG.Polygon.prototype = {
     // check whether the polygon is convex (it should be, otherwise we will get unexpected results)
     checkIfConvex: function () {
       if (!CSG.Polygon.verticesConvex(this.vertices, this.plane.normal)) {
         CSG.Polygon.verticesConvex(this.vertices, this.plane.normal)
         return false;
       }
       return true;
     },
     setColor: function (args) {
       var newshared = CSG.Polygon.Shared.fromColor.apply(this, arguments)
       this.shared = newshared
       return this
     },
     getSignedVolume: function () {
       var signedVolume = 0
       for (var i = 0; i < this.vertices.length - 2; i++) {
         signedVolume += this.vertices[0].pos.dot(this.vertices[i + 1].pos
           .cross(this.vertices[i + 2].pos))
       }
       signedVolume /= 6
       return signedVolume
     },
     // Note: could calculate vectors only once to speed up
     getArea: function () {
       var polygonArea = 0
       for (var i = 0; i < this.vertices.length - 2; i++) {
         polygonArea += this.vertices[i + 1].pos.minus(this.vertices[0].pos)
           .cross(this.vertices[i + 2].pos.minus(this.vertices[i + 1].pos)).length()
       }
       polygonArea /= 2
       return polygonArea
     },
     // accepts array of features to calculate
     // returns array of results
     getTetraFeatures: function (features) {
       var result = []
       features.forEach(function (feature) {
         if (feature === 'volume') {
           result.push(this.getSignedVolume())
         } else if (feature === 'area') {
           result.push(this.getArea())
         }
       }, this)
       return result
     },
     // Extrude a polygon into the direction offsetvector
     // Returns a CSG object
     extrude: function (offsetvector) {
       var newpolygons = []
       var polygon1 = this
       var direction = polygon1.plane.normal.dot(offsetvector)
       if (direction > 0) {
         polygon1 = polygon1.flipped()
       }
       newpolygons.push(polygon1)
       var polygon2 = polygon1.translate(offsetvector)
       var numvertices = this.vertices.length
       for (var i = 0; i < numvertices; i++) {
         var sidefacepoints = []
         var nexti = (i < (numvertices - 1)) ? i + 1 : 0
         sidefacepoints.push(polygon1.vertices[i].pos)
         sidefacepoints.push(polygon2.vertices[i].pos)
         sidefacepoints.push(polygon2.vertices[nexti].pos)
         sidefacepoints.push(polygon1.vertices[nexti].pos)
         var sidefacepolygon = CSG.Polygon.createFromPoints(sidefacepoints, this.shared)
         newpolygons.push(sidefacepolygon)
       }
       polygon2 = polygon2.flipped()
       newpolygons.push(polygon2)
       return CSG.fromPolygons(newpolygons)
     },
     translate: function (offset) {
       return this.transform(CSG.Matrix4x4.translation(offset))
     },
     // returns an array with a CSG.Vector3D (center point) and a radius
     boundingSphere: function () {
       if (!this.cachedBoundingSphere) {
         var box = this.boundingBox()
         var middle = box[0].plus(box[1]).times(0.5)
         var radius3 = box[1].minus(middle)
         var radius = radius3.length()
         this.cachedBoundingSphere = [middle, radius]
       }
       return this.cachedBoundingSphere
     },
     // returns an array of two CSG.Vector3Ds (minimum coordinates and maximum coordinates)
     boundingBox: function () {
       if (!this.cachedBoundingBox) {
         var minpoint, maxpoint
         var vertices = this.vertices
         var numvertices = vertices.length
         if (numvertices === 0) {
           minpoint = new CSG.Vector3D(0, 0, 0)
         } else {
           minpoint = vertices[0].pos
         }
         maxpoint = minpoint
         for (var i = 1; i < numvertices; i++) {
           var point = vertices[i].pos
           minpoint = minpoint.min(point)
           maxpoint = maxpoint.max(point)
         }
         this.cachedBoundingBox = [minpoint, maxpoint]
       }
       return this.cachedBoundingBox
     },
     flipped: function () {
       var newvertices = this.vertices.map(function (v) {
         return v.flipped()
       })
       newvertices.reverse()
       var newplane = this.plane.flipped()
       return new CSG.Polygon(newvertices, this.shared, newplane)
     },
     // Affine transformation of polygon. Returns a new CSG.Polygon
     transform: function (matrix4x4) {
       var newvertices = this.vertices.map(function (v) {
         return v.transform(matrix4x4)
       })
       var newplane = this.plane.transform(matrix4x4)
       if (matrix4x4.isMirroring()) {
         // need to reverse the vertex order
         // in order to preserve the inside/outside orientation:
         newvertices.reverse()
       }
       return new CSG.Polygon(newvertices, this.shared, newplane)
     },
     toString: function () {
       var result = "Polygon plane: " + this.plane.toString() + "\n"
       this.vertices.map(function (vertex) {
         result += "  " + vertex.toString() + "\n"
       })
       return result
     },
     // project the 3D polygon onto a plane
     projectToOrthoNormalBasis: function (orthobasis) {
       var points2d = this.vertices.map(function (vertex) {
         return orthobasis.to2D(vertex.pos)
       })
       var result = CAG.fromPointsNoCheck(points2d)
       var area = result.area()
       if (Math.abs(area) < 1e-5) {
         // the polygon was perpendicular to the orthnormal plane. The resulting 2D polygon would be degenerate
         // return an empty area instead:
         result = new CAG()
       } else if (area < 0) {
         result = result.flipped()
       }
       return result
     },
     /**
      * Creates solid from slices (CSG.Polygon) by generating walls
      * @param {Object} options Solid generating options
      *  - numslices {Number} Number of slices to be generated
      *  - callback(t, slice) {Function} Callback function generating slices.
      *          arguments: t = [0..1], slice = [0..numslices - 1]
      *          return: CSG.Polygon or null to skip
      *  - loop {Boolean} no flats, only walls, it's used to generate solids like a tor
      */
     solidFromSlices: function (options) {
       var polygons = [],
         csg = null,
         prev = null,
         bottom = null,
         top = null,
         numSlices = 2,
         bLoop = false,
         fnCallback,
         flipped = null
       if (options) {
         bLoop = Boolean(options['loop'])
         if (options.numslices)
           numSlices = options.numslices
         if (options.callback)
           fnCallback = options.callback
       }
       if (!fnCallback) {
         var square = new CSG.Polygon.createFromPoints([
           [0, 0, 0],
           [1, 0, 0],
           [1, 1, 0],
           [0, 1, 0]
         ])
         fnCallback = function (t, slice) {
           return t === 0 || t === 1 ? square.translate([0, 0, t]) : null
         }
       }
       for (var i = 0, iMax = numSlices - 1; i <= iMax; i++) {
         csg = fnCallback.call(this, i / iMax, i)
         if (csg) {
           if (!(csg instanceof CSG.Polygon)) {
             throw new Error("CSG.Polygon.solidFromSlices callback error: CSG.Polygon expected")
           }
           //csg.checkIfConvex()
           if (prev) { //generate walls
             if (flipped === null) { //not generated yet
               flipped = prev.plane.signedDistanceToPoint(csg.vertices[0].pos) < 0
             }
             this._addWalls(polygons, prev, csg, flipped)
           } else { //the first - will be a bottom
             bottom = csg
           }
           prev = csg
         } //callback can return null to skip that slice
       }
       top = csg
       if (bLoop) {
         var bSameTopBottom = bottom.vertices.length === top.vertices.length &&
           bottom.vertices.every(function (v, index) {
             return v.pos.equals(top.vertices[index].pos)
           })
           //if top and bottom are not the same -
           //generate walls between them
         if (!bSameTopBottom) {
           this._addWalls(polygons, top, bottom, flipped)
         } //else - already generated
       } else {
         //save top and bottom
         //TODO: flip if necessary
         polygons.unshift(flipped ? bottom : bottom.flipped())
         polygons.push(flipped ? top.flipped() : top)
       }
       return CSG.fromPolygons(polygons)
     },
     /**
      *
      * @param walls Array of wall polygons
      * @param bottom Bottom polygon
      * @param top Top polygon
      */
     _addWalls: function (walls, bottom, top, bFlipped) {
       var bottomPoints = bottom.vertices.slice(0), // make a copy
         topPoints = top.vertices.slice(0), // make a copy
         color = top.shared || null
         //check if bottom perimeter is closed
       if (!bottomPoints[0].pos.equals(bottomPoints[bottomPoints.length - 1].pos)) {
         bottomPoints.push(bottomPoints[0])
       }
       //check if top perimeter is closed
       if (!topPoints[0].pos.equals(topPoints[topPoints.length - 1].pos)) {
         topPoints.push(topPoints[0])
       }
       if (bFlipped) {
         bottomPoints = bottomPoints.reverse()
         topPoints = topPoints.reverse()
       }
       var iTopLen = topPoints.length - 1,
         iBotLen = bottomPoints.length - 1,
         iExtra = iTopLen - iBotLen, //how many extra triangles we need
         bMoreTops = iExtra > 0,
         bMoreBottoms = iExtra < 0
       var aMin = [] //indexes to start extra triangles (polygon with minimal square)
         //init - we need exactly /iExtra/ small triangles
       for (var i = Math.abs(iExtra); i > 0; i--) {
         aMin.push({
           len: Infinity,
           index: -1
         })
       }
       var len
       if (bMoreBottoms) {
         for (var i = 0; i < iBotLen; i++) {
           len = bottomPoints[i].pos.distanceToSquared(bottomPoints[i + 1].pos)
             //find the element to replace
           for (var j = aMin.length - 1; j >= 0; j--) {
             if (aMin[j].len > len) {
               aMin[j].len = len
               aMin.index = j
               break
             }
           } //for
         }
       } else if (bMoreTops) {
         for (var i = 0; i < iTopLen; i++) {
           len = topPoints[i].pos.distanceToSquared(topPoints[i + 1].pos)
             //find the element to replace
           for (var j = aMin.length - 1; j >= 0; j--) {
             if (aMin[j].len > len) {
               aMin[j].len = len
               aMin.index = j
               break
             }
           } //for
         }
       } //if
       //sort by index
       aMin.sort(fnSortByIndex)
       var getTriangle = function addWallsPutTriangle(pointA, pointB, pointC, color) {
         return new CSG.Polygon([pointA, pointB, pointC], color)
           //return bFlipped ? triangle.flipped() : triangle;
       }
       var bpoint = bottomPoints[0],
         tpoint = topPoints[0],
         secondPoint,
         nBotFacet, nTopFacet //length of triangle facet side
       for (var iB = 0, iT = 0, iMax = iTopLen + iBotLen; iB + iT < iMax;) {
         if (aMin.length) {
           if (bMoreTops && iT === aMin[0].index) { //one vertex is on the bottom, 2 - on the top
             secondPoint = topPoints[++iT]
               //console.log('<<< extra top: ' + secondPoint + ', ' + tpoint + ', bottom: ' + bpoint);
             walls.push(getTriangle(
               secondPoint, tpoint, bpoint, color
             ))
             tpoint = secondPoint
             aMin.shift()
             continue
           } else if (bMoreBottoms && iB === aMin[0].index) {
             secondPoint = bottomPoints[++iB]
             walls.push(getTriangle(
               tpoint, bpoint, secondPoint, color
             ))
             bpoint = secondPoint
             aMin.shift()
             continue
           }
         }
         //choose the shortest path
         if (iB < iBotLen) { //one vertex is on the top, 2 - on the bottom
           nBotFacet = tpoint.pos.distanceToSquared(bottomPoints[iB + 1].pos)
         } else {
           nBotFacet = Infinity
         }
         if (iT < iTopLen) { //one vertex is on the bottom, 2 - on the top
           nTopFacet = bpoint.pos.distanceToSquared(topPoints[iT + 1].pos)
         } else {
           nTopFacet = Infinity
         }
         if (nBotFacet <= nTopFacet) {
           secondPoint = bottomPoints[++iB]
           walls.push(getTriangle(
             tpoint, bpoint, secondPoint, color
           ))
           bpoint = secondPoint
         } else if (iT < iTopLen) { //nTopFacet < Infinity
           secondPoint = topPoints[++iT]
             //console.log('<<< top: ' + secondPoint + ', ' + tpoint + ', bottom: ' + bpoint);
           walls.push(getTriangle(
             secondPoint, tpoint, bpoint, color
           ))
           tpoint = secondPoint
         }
       }
       return walls
     }
   }
   CSG.Polygon.verticesConvex = function (vertices, planenormal) {
     var numvertices = vertices.length
     if (numvertices > 2) {
       var prevprevpos = vertices[numvertices - 2].pos
       var prevpos = vertices[numvertices - 1].pos
       for (var i = 0; i < numvertices; i++) {
         var pos = vertices[i].pos
         if (!CSG.Polygon.isConvexPoint(prevprevpos, prevpos, pos, planenormal)) {
           return false
         }
         prevprevpos = prevpos
         prevpos = pos
       }
     }
     return true
   }
   // Create a polygon from the given points
   CSG.Polygon.createFromPoints = function (points, shared, plane) {
     var normal
     if (arguments.length < 3) {
       // initially set a dummy vertex normal:
       normal = new CSG.Vector3D(0, 0, 0)
     } else {
       normal = plane.normal
     }
     var vertices = []
     points.map(function (p) {
       var vec = new CSG.Vector3D(p)
       var vertex = new CSG.Vertex(vec)
       vertices.push(vertex)
     })
     var polygon
     if (arguments.length < 3) {
       polygon = new CSG.Polygon(vertices, shared)
     } else {
       polygon = new CSG.Polygon(vertices, shared, plane)
     }
     return polygon
   }
   // calculate whether three points form a convex corner
   //  prevpoint, point, nextpoint: the 3 coordinates (CSG.Vector3D instances)
   //  normal: the normal vector of the plane
   CSG.Polygon.isConvexPoint = function (prevpoint, point, nextpoint, normal) {
     var crossproduct = point.minus(prevpoint).cross(nextpoint.minus(point))
     var crossdotnormal = crossproduct.dot(normal)
     return (crossdotnormal >= 0)
   }
   CSG.Polygon.isStrictlyConvexPoint = function (prevpoint, point, nextpoint, normal) {
     var crossproduct = point.minus(prevpoint).cross(nextpoint.minus(point))
     var crossdotnormal = crossproduct.dot(normal)
     return (crossdotnormal >= 1e-5)
   }
   // # class CSG.Polygon.Shared
   // Holds the shared properties for each polygon (currently only color)
   // Constructor expects a 4 element array [r,g,b,a], values from 0 to 1, or null
   CSG.Polygon.Shared = function (color) {
     if (color !== null) {
       if (color.length !== 4) {
         throw new Error("Expecting 4 element array")
       }
     }
     this.color = color
   }
   CSG.Polygon.Shared.fromObject = function (obj) {
       return new CSG.Polygon.Shared(obj.color)
     }
     // Create CSG.Polygon.Shared from a color, can be called as follows:
     // var s = CSG.Polygon.Shared.fromColor(r,g,b [,a])
     // var s = CSG.Polygon.Shared.fromColor([r,g,b [,a]])
   CSG.Polygon.Shared.fromColor = function (args) {
     var color
     if (arguments.length === 1) {
       color = arguments[0].slice() // make deep copy
     } else {
       color = []
       for (var i = 0; i < arguments.length; i++) {
         color.push(arguments[i])
       }
     }
     if (color.length === 3) {
       color.push(1)
     } else if (color.length !== 4) {
       throw new Error("setColor expects either an array with 3 or 4 elements, or 3 or 4 parameters.")
     }
     return new CSG.Polygon.Shared(color)
   }
   CSG.Polygon.Shared.prototype = {
     getTag: function () {
       var result = this.tag
       if (!result) {
         result = CSG.getTag()
         this.tag = result
       }
       return result
     },
     // get a string uniquely identifying this object
     getHash: function () {
       if (!this.color) return "null"
       return this.color.join("/")
     }
   }
   CSG.Polygon.defaultShared = new CSG.Polygon.Shared(null)
     // # class PolygonTreeNode
     // This class manages hierarchical splits of polygons
     // At the top is a root node which doesn hold a polygon, only child PolygonTreeNodes
     // Below that are zero or more 'top' nodes; each holds a polygon. The polygons can be in different planes
     // splitByPlane() splits a node by a plane. If the plane intersects the polygon, two new child nodes
     // are created holding the splitted polygon.
     // getPolygons() retrieves the polygon from the tree. If for PolygonTreeNode the polygon is split but
     // the two split parts (child nodes) are still intact, then the unsplit polygon is returned.
     // This ensures that we can safely split a polygon into many fragments. If the fragments are untouched,
     //  getPolygons() will return the original unsplit polygon instead of the fragments.
     // remove() removes a polygon from the tree. Once a polygon is removed, the parent polygons are invalidated
     // since they are no longer intact.
     // constructor creates the root node:
   CSG.PolygonTreeNode = function () {
     this.parent = null
     this.children = []
     this.polygon = null
     this.removed = false
   }
   CSG.PolygonTreeNode.prototype = {
       // fill the tree with polygons. Should be called on the root node only; child nodes must
       // always be a derivate (split) of the parent node.
       addPolygons: function (polygons) {
         if (!this.isRootNode())
         // new polygons can only be added to root node; children can only be splitted polygons
           throw new Error("Assertion failed")
         var _this = this
         polygons.map(function (polygon) {
           _this.addChild(polygon)
         })
       },
       // remove a node
       // - the siblings become toplevel nodes
       // - the parent is removed recursively
       remove: function () {
         if (!this.removed) {
           this.removed = true
           if (_CSGDEBUG) {
             if (this.isRootNode()) throw new Error("Assertion failed") // can't remove root node
             if (this.children.length) throw new Error("Assertion failed") // we shouldn't remove nodes with children
           }
           // remove ourselves from the parent's children list:
           var parentschildren = this.parent.children
           var i = parentschildren.indexOf(this)
           if (i < 0) throw new Error("Assertion failed")
           parentschildren.splice(i, 1)
             // invalidate the parent's polygon, and of all parents above it:
           this.parent.recursivelyInvalidatePolygon()
         }
       },
       isRemoved: function () {
         return this.removed
       },
       isRootNode: function () {
         return !this.parent
       },
       // invert all polygons in the tree. Call on the root node
       invert: function () {
         if (!this.isRootNode()) throw new Error("Assertion failed") // can only call this on the root node
         this.invertSub()
       },
       getPolygon: function () {
         if (!this.polygon) throw new Error("Assertion failed") // doesn't have a polygon, which means that it has been broken down
         return this.polygon
       },
       getPolygons: function (result) {
         var children = [this]
         var queue = [children]
         var i, j, l, node
         for (i = 0; i < queue.length; ++i) { // queue size can change in loop, don't cache length
           children = queue[i]
           for (j = 0, l = children.length; j < l; j++) { // ok to cache length
             node = children[j]
             if (node.polygon) {
               // the polygon hasn't been broken yet. We can ignore the children and return our polygon:
               result.push(node.polygon)
             } else {
               // our polygon has been split up and broken, so gather all subpolygons from the children
               queue.push(node.children)
             }
           }
         }
       },
       // split the node by a plane; add the resulting nodes to the frontnodes and backnodes array
       // If the plane doesn't intersect the polygon, the 'this' object is added to one of the arrays
       // If the plane does intersect the polygon, two new child nodes are created for the front and back fragments,
       //  and added to both arrays.
       splitByPlane: function (plane, coplanarfrontnodes, coplanarbacknodes, frontnodes, backnodes) {
         if (this.children.length) {
           var queue = [this.children],
             i, j, l, node, nodes
           for (i = 0; i < queue.length; i++) { // queue.length can increase, do not cache
             nodes = queue[i]
             for (j = 0, l = nodes.length; j < l; j++) { // ok to cache length
               node = nodes[j]
               if (node.children.length) {
                 queue.push(node.children)
               } else {
                 // no children. Split the polygon:
                 node._splitByPlane(plane, coplanarfrontnodes, coplanarbacknodes, frontnodes, backnodes)
               }
             }
           }
         } else {
           this._splitByPlane(plane, coplanarfrontnodes, coplanarbacknodes, frontnodes, backnodes)
         }
       },
       // only to be called for nodes with no children
       _splitByPlane: function (plane, coplanarfrontnodes, coplanarbacknodes, frontnodes, backnodes) {
         var polygon = this.polygon
         if (polygon) {
           var bound = polygon.boundingSphere()
           var sphereradius = bound[1] + 1e-4
           var planenormal = plane.normal
           var spherecenter = bound[0]
           var d = planenormal.dot(spherecenter) - plane.w
           if (d > sphereradius) {
             frontnodes.push(this)
           } else if (d < -sphereradius) {
             backnodes.push(this)
           } else {
             var splitresult = plane.splitPolygon(polygon)
             switch (splitresult.type) {
             case 0:
               // coplanar front:
               coplanarfrontnodes.push(this)
               break
             case 1:
               // coplanar back:
               coplanarbacknodes.push(this)
               break
             case 2:
               // front:
               frontnodes.push(this)
               break
             case 3:
               // back:
               backnodes.push(this)
               break
             case 4:
               // spanning:
               if (splitresult.front) {
                 var frontnode = this.addChild(splitresult.front)
                 frontnodes.push(frontnode)
               }
               if (splitresult.back) {
                 var backnode = this.addChild(splitresult.back)
                 backnodes.push(backnode)
               }
               break
             }
           }
         }
       },
       // PRIVATE methods from here:
       // add child to a node
       // this should be called whenever the polygon is split
       // a child should be created for every fragment of the split polygon
       // returns the newly created child
       addChild: function (polygon) {
         var newchild = new CSG.PolygonTreeNode()
         newchild.parent = this
         newchild.polygon = polygon
         this.children.push(newchild)
         return newchild
       },
       invertSub: function () {
         var children = [this]
         var queue = [children]
         var i, j, l, node
         for (i = 0; i < queue.length; i++) {
           children = queue[i]
           for (j = 0, l = children.length; j < l; j++) {
             node = children[j]
             if (node.polygon) {
               node.polygon = node.polygon.flipped()
             }
             queue.push(node.children)
           }
         }
       },
       recursivelyInvalidatePolygon: function () {
         var node = this
         while (node.polygon) {
           node.polygon = null
           if (node.parent) {
             node = node.parent
           }
         }
       }
     }
     // # class Tree
     // This is the root of a BSP tree
     // We are using this separate class for the root of the tree, to hold the PolygonTreeNode root
     // The actual tree is kept in this.rootnode
   CSG.Tree = function (polygons) {
     this.polygonTree = new CSG.PolygonTreeNode()
     this.rootnode = new CSG.Node(null)
     if (polygons) this.addPolygons(polygons)
   }
   CSG.Tree.prototype = {
       invert: function () {
         this.polygonTree.invert()
         this.rootnode.invert()
       },
       // Remove all polygons in this BSP tree that are inside the other BSP tree
       // `tree`.
       clipTo: function (tree, alsoRemovecoplanarFront) {
         alsoRemovecoplanarFront = alsoRemovecoplanarFront ? true : false
         this.rootnode.clipTo(tree, alsoRemovecoplanarFront)
       },
       allPolygons: function () {
         var result = []
         this.polygonTree.getPolygons(result)
         return result
       },
       addPolygons: function (polygons) {
         var _this = this
         var polygontreenodes = polygons.map(function (p) {
           return _this.polygonTree.addChild(p)
         })
         this.rootnode.addPolygonTreeNodes(polygontreenodes)
       }
     }
     // # class Node
     // Holds a node in a BSP tree. A BSP tree is built from a collection of polygons
     // by picking a polygon to split along.
     // Polygons are not stored directly in the tree, but in PolygonTreeNodes, stored in
     // this.polygontreenodes. Those PolygonTreeNodes are children of the owning
     // CSG.Tree.polygonTree
     // This is not a leafy BSP tree since there is
     // no distinction between internal and leaf nodes.
   CSG.Node = function (parent) {
     this.plane = null
     this.front = null
     this.back = null
     this.polygontreenodes = []
     this.parent = parent
   }
   CSG.Node.prototype = {
       // Convert solid space to empty space and empty space to solid space.
       invert: function () {
         var queue = [this]
         var i, node
         for (var i = 0; i < queue.length; i++) {
           node = queue[i]
           if (node.plane) node.plane = node.plane.flipped()
           if (node.front) queue.push(node.front)
           if (node.back) queue.push(node.back)
           var temp = node.front
           node.front = node.back
           node.back = temp
         }
       },
       // clip polygontreenodes to our plane
       // calls remove() for all clipped PolygonTreeNodes
       clipPolygons: function (polygontreenodes, alsoRemovecoplanarFront) {
         var args = {
           'node': this,
           'polygontreenodes': polygontreenodes
         }
         var node
         var stack = []
         do {
           node = args.node
           polygontreenodes = args.polygontreenodes
             // begin "function"
           if (node.plane) {
             var backnodes = []
             var frontnodes = []
             var coplanarfrontnodes = alsoRemovecoplanarFront ? backnodes : frontnodes
             var plane = node.plane
             var numpolygontreenodes = polygontreenodes.length
             for (i = 0; i < numpolygontreenodes; i++) {
               var node1 = polygontreenodes[i]
               if (!node1.isRemoved()) {
                 node1.splitByPlane(plane, coplanarfrontnodes, backnodes, frontnodes, backnodes)
               }
             }
             if (node.front && (frontnodes.length > 0)) {
               stack.push({
                 'node': node.front,
                 'polygontreenodes': frontnodes
               })
             }
             var numbacknodes = backnodes.length
             if (node.back && (numbacknodes > 0)) {
               stack.push({
                 'node': node.back,
                 'polygontreenodes': backnodes
               })
             } else {
               // there's nothing behind this plane. Delete the nodes behind this plane:
               for (var i = 0; i < numbacknodes; i++) {
                 backnodes[i].remove()
               }
             }
           }
           args = stack.pop()
         } while (typeof (args) !== 'undefined')
       },
       // Remove all polygons in this BSP tree that are inside the other BSP tree
       // `tree`.
       clipTo: function (tree, alsoRemovecoplanarFront) {
         var node = this,
           stack = []
         do {
           if (node.polygontreenodes.length > 0) {
             tree.rootnode.clipPolygons(node.polygontreenodes, alsoRemovecoplanarFront)
           }
           if (node.front) stack.push(node.front)
           if (node.back) stack.push(node.back)
           node = stack.pop()
         } while (typeof (node) !== 'undefined')
       },
       addPolygonTreeNodes: function (polygontreenodes) {
         var args = {
           'node': this,
           'polygontreenodes': polygontreenodes
         }
         var node
         var stack = []
         do {
           node = args.node
           polygontreenodes = args.polygontreenodes
           if (polygontreenodes.length === 0) {
             args = stack.pop()
             continue
           }
           var _this = node
           if (!node.plane) {
             var bestplane = polygontreenodes[0].getPolygon().plane
             node.plane = bestplane
           }
           var frontnodes = []
           var backnodes = []
           for (var i = 0, n = polygontreenodes.length; i < n; ++i) {
             polygontreenodes[i].splitByPlane(_this.plane, _this.polygontreenodes, backnodes, frontnodes, backnodes)
           }
           if (frontnodes.length > 0) {
             if (!node.front) node.front = new CSG.Node(node)
             stack.push({
               'node': node.front,
               'polygontreenodes': frontnodes
             })
           }
           if (backnodes.length > 0) {
             if (!node.back) node.back = new CSG.Node(node)
             stack.push({
               'node': node.back,
               'polygontreenodes': backnodes
             })
           }
           args = stack.pop()
         } while (typeof (args) !== 'undefined')
       },
       getParentPlaneNormals: function (normals, maxdepth) {
         if (maxdepth > 0) {
           if (this.parent) {
             normals.push(this.parent.plane.normal)
             this.parent.getParentPlaneNormals(normals, maxdepth - 1)
           }
         }
       }
     }
     //////////
     // # class Matrix4x4:
     // Represents a 4x4 matrix. Elements are specified in row order
   CSG.Matrix4x4 = function (elements) {
     if (arguments.length >= 1) {
       this.elements = elements
     } else {
       // if no arguments passed: create unity matrix
       this.elements = [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]
     }
   }
   CSG.Matrix4x4.prototype = {
       plus: function (m) {
         var r = []
         for (var i = 0; i < 16; i++) {
           r[i] = this.elements[i] + m.elements[i]
         }
         return new CSG.Matrix4x4(r)
       },
       minus: function (m) {
         var r = []
         for (var i = 0; i < 16; i++) {
           r[i] = this.elements[i] - m.elements[i]
         }
         return new CSG.Matrix4x4(r)
       },
       // right multiply by another 4x4 matrix:
       multiply: function (m) {
         // cache elements in local variables, for speedup:
         var this0 = this.elements[0]
         var this1 = this.elements[1]
         var this2 = this.elements[2]
         var this3 = this.elements[3]
         var this4 = this.elements[4]
         var this5 = this.elements[5]
         var this6 = this.elements[6]
         var this7 = this.elements[7]
         var this8 = this.elements[8]
         var this9 = this.elements[9]
         var this10 = this.elements[10]
         var this11 = this.elements[11]
         var this12 = this.elements[12]
         var this13 = this.elements[13]
         var this14 = this.elements[14]
         var this15 = this.elements[15]
         var m0 = m.elements[0]
         var m1 = m.elements[1]
         var m2 = m.elements[2]
         var m3 = m.elements[3]
         var m4 = m.elements[4]
         var m5 = m.elements[5]
         var m6 = m.elements[6]
         var m7 = m.elements[7]
         var m8 = m.elements[8]
         var m9 = m.elements[9]
         var m10 = m.elements[10]
         var m11 = m.elements[11]
         var m12 = m.elements[12]
         var m13 = m.elements[13]
         var m14 = m.elements[14]
         var m15 = m.elements[15]
         var result = []
         result[0] = this0 * m0 + this1 * m4 + this2 * m8 + this3 * m12
         result[1] = this0 * m1 + this1 * m5 + this2 * m9 + this3 * m13
         result[2] = this0 * m2 + this1 * m6 + this2 * m10 + this3 * m14
         result[3] = this0 * m3 + this1 * m7 + this2 * m11 + this3 * m15
         result[4] = this4 * m0 + this5 * m4 + this6 * m8 + this7 * m12
         result[5] = this4 * m1 + this5 * m5 + this6 * m9 + this7 * m13
         result[6] = this4 * m2 + this5 * m6 + this6 * m10 + this7 * m14
         result[7] = this4 * m3 + this5 * m7 + this6 * m11 + this7 * m15
         result[8] = this8 * m0 + this9 * m4 + this10 * m8 + this11 * m12
         result[9] = this8 * m1 + this9 * m5 + this10 * m9 + this11 * m13
         result[10] = this8 * m2 + this9 * m6 + this10 * m10 + this11 * m14
         result[11] = this8 * m3 + this9 * m7 + this10 * m11 + this11 * m15
         result[12] = this12 * m0 + this13 * m4 + this14 * m8 + this15 * m12
         result[13] = this12 * m1 + this13 * m5 + this14 * m9 + this15 * m13
         result[14] = this12 * m2 + this13 * m6 + this14 * m10 + this15 * m14
         result[15] = this12 * m3 + this13 * m7 + this14 * m11 + this15 * m15
         return new CSG.Matrix4x4(result)
       },
       clone: function () {
         var elements = this.elements.map(function (p) {
           return p
         })
         return new CSG.Matrix4x4(elements)
       },
       // Right multiply the matrix by a CSG.Vector3D (interpreted as 3 row, 1 column)
       // (result = M*v)
       // Fourth element is taken as 1
       rightMultiply1x3Vector: function (v) {
         var v0 = v._x
         var v1 = v._y
         var v2 = v._z
         var v3 = 1
         var x = v0 * this.elements[0] + v1 * this.elements[1] + v2 * this.elements[2] + v3 * this.elements[3]
         var y = v0 * this.elements[4] + v1 * this.elements[5] + v2 * this.elements[6] + v3 * this.elements[7]
         var z = v0 * this.elements[8] + v1 * this.elements[9] + v2 * this.elements[10] + v3 * this.elements[11]
         var w = v0 * this.elements[12] + v1 * this.elements[13] + v2 * this.elements[14] + v3 * this.elements[15]
           // scale such that fourth element becomes 1:
         if (w !== 1) {
           var invw = 1.0 / w
           x *= invw
           y *= invw
           z *= invw
         }
         return new CSG.Vector3D(x, y, z)
       },
       // Multiply a CSG.Vector3D (interpreted as 3 column, 1 row) by this matrix
       // (result = v*M)
       // Fourth element is taken as 1
       leftMultiply1x3Vector: function (v) {
         var v0 = v._x
         var v1 = v._y
         var v2 = v._z
         var v3 = 1
         var x = v0 * this.elements[0] + v1 * this.elements[4] + v2 * this.elements[8] + v3 * this.elements[12]
         var y = v0 * this.elements[1] + v1 * this.elements[5] + v2 * this.elements[9] + v3 * this.elements[13]
         var z = v0 * this.elements[2] + v1 * this.elements[6] + v2 * this.elements[10] + v3 * this.elements[14]
         var w = v0 * this.elements[3] + v1 * this.elements[7] + v2 * this.elements[11] + v3 * this.elements[15]
           // scale such that fourth element becomes 1:
         if (w !== 1) {
           var invw = 1.0 / w
           x *= invw
           y *= invw
           z *= invw
         }
         return new CSG.Vector3D(x, y, z)
       },
       // Right multiply the matrix by a CSG.Vector2D (interpreted as 2 row, 1 column)
       // (result = M*v)
       // Fourth element is taken as 1
       rightMultiply1x2Vector: function (v) {
         var v0 = v.x
         var v1 = v.y
         var v2 = 0
         var v3 = 1
         var x = v0 * this.elements[0] + v1 * this.elements[1] + v2 * this.elements[2] + v3 * this.elements[3]
         var y = v0 * this.elements[4] + v1 * this.elements[5] + v2 * this.elements[6] + v3 * this.elements[7]
         var z = v0 * this.elements[8] + v1 * this.elements[9] + v2 * this.elements[10] + v3 * this.elements[11]
         var w = v0 * this.elements[12] + v1 * this.elements[13] + v2 * this.elements[14] + v3 * this.elements[15]
           // scale such that fourth element becomes 1:
         if (w !== 1) {
           var invw = 1.0 / w
           x *= invw
           y *= invw
           z *= invw
         }
         return new CSG.Vector2D(x, y)
       },
       // Multiply a CSG.Vector2D (interpreted as 2 column, 1 row) by this matrix
       // (result = v*M)
       // Fourth element is taken as 1
       leftMultiply1x2Vector: function (v) {
         var v0 = v.x
         var v1 = v.y
         var v2 = 0
         var v3 = 1
         var x = v0 * this.elements[0] + v1 * this.elements[4] + v2 * this.elements[8] + v3 * this.elements[12]
         var y = v0 * this.elements[1] + v1 * this.elements[5] + v2 * this.elements[9] + v3 * this.elements[13]
         var z = v0 * this.elements[2] + v1 * this.elements[6] + v2 * this.elements[10] + v3 * this.elements[14]
         var w = v0 * this.elements[3] + v1 * this.elements[7] + v2 * this.elements[11] + v3 * this.elements[15]
           // scale such that fourth element becomes 1:
         if (w !== 1) {
           var invw = 1.0 / w
           x *= invw
           y *= invw
           z *= invw
         }
         return new CSG.Vector2D(x, y)
       },
       // determine whether this matrix is a mirroring transformation
       isMirroring: function () {
         var u = new CSG.Vector3D(this.elements[0], this.elements[4], this.elements[8])
         var v = new CSG.Vector3D(this.elements[1], this.elements[5], this.elements[9])
         var w = new CSG.Vector3D(this.elements[2], this.elements[6], this.elements[10])
           // for a true orthogonal, non-mirrored base, u.cross(v) === w
           // If they have an opposite direction then we are mirroring
         var mirrorvalue = u.cross(v).dot(w)
         var ismirror = (mirrorvalue < 0)
         return ismirror
       }
     }
     // return the unity matrix
   CSG.Matrix4x4.unity = function () {
       return new CSG.Matrix4x4()
     }
     // Create a rotation matrix for rotating around the x axis
   CSG.Matrix4x4.rotationX = function (degrees) {
       var radians = degrees * Math.PI * (1.0 / 180.0)
       var cos = Math.cos(radians)
       var sin = Math.sin(radians)
       var els = [
         1, 0, 0, 0, 0, cos, sin, 0, 0, -sin, cos, 0, 0, 0, 0, 1
       ]
       return new CSG.Matrix4x4(els)
     }
     // Create a rotation matrix for rotating around the y axis
   CSG.Matrix4x4.rotationY = function (degrees) {
     var radians = degrees * Math.PI * (1.0 / 180.0)
     var cos = Math.cos(radians)
     var sin = Math.sin(radians)
     var els = [
       cos, 0, -sin, 0, 0, 1, 0, 0, sin, 0, cos, 0, 0, 0, 0, 1
     ]
     return new CSG.Matrix4x4(els)
   }
   // Create a rotation matrix for rotating around the z axis
   CSG.Matrix4x4.rotationZ = function (degrees) {
     var radians = degrees * Math.PI * (1.0 / 180.0)
     var cos = Math.cos(radians)
     var sin = Math.sin(radians)
     var els = [
       cos, sin, 0, 0, -sin, cos, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1
     ]
     return new CSG.Matrix4x4(els)
   }
   // Matrix for rotation about arbitrary point and axis
   CSG.Matrix4x4.rotation = function (rotationCenter, rotationAxis, degrees) {
     rotationCenter = new CSG.Vector3D(rotationCenter)
     rotationAxis = new CSG.Vector3D(rotationAxis)
     var rotationPlane = CSG.Plane.fromNormalAndPoint(rotationAxis, rotationCenter)
     var orthobasis = new CSG.OrthoNormalBasis(rotationPlane)
     var transformation = CSG.Matrix4x4.translation(rotationCenter.negated())
     transformation = transformation.multiply(orthobasis.getProjectionMatrix())
     transformation = transformation.multiply(CSG.Matrix4x4.rotationZ(degrees))
     transformation = transformation.multiply(orthobasis.getInverseProjectionMatrix())
     transformation = transformation.multiply(CSG.Matrix4x4.translation(rotationCenter))
     return transformation
   }
   // Create an affine matrix for translation:
   CSG.Matrix4x4.translation = function (v) {
     // parse as CSG.Vector3D, so we can pass an array or a CSG.Vector3D
     var vec = new CSG.Vector3D(v)
     var els = [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, vec.x, vec.y, vec.z, 1]
     return new CSG.Matrix4x4(els)
   }
   // Create an affine matrix for mirroring into an arbitrary plane:
   CSG.Matrix4x4.mirroring = function (plane) {
     var nx = plane.normal.x
     var ny = plane.normal.y
     var nz = plane.normal.z
     var w = plane.w
     var els = [
       (1.0 - 2.0 * nx * nx), (-2.0 * ny * nx), (-2.0 * nz * nx), 0, (-2.0 * nx * ny), (1.0 - 2.0 * ny * ny), (-2.0 * nz * ny), 0, (-2.0 * nx * nz), (-2.0 * ny * nz), (1.0 - 2.0 * nz * nz), 0, (2.0 * nx * w), (2.0 * ny * w), (2.0 * nz * w), 1
     ]
     return new CSG.Matrix4x4(els)
   }
   // Create an affine matrix for scaling:
   CSG.Matrix4x4.scaling = function (v) {
     // parse as CSG.Vector3D, so we can pass an array or a CSG.Vector3D
     var vec = new CSG.Vector3D(v)
     var els = [
       vec.x, 0, 0, 0, 0, vec.y, 0, 0, 0, 0, vec.z, 0, 0, 0, 0, 1
     ]
     return new CSG.Matrix4x4(els)
   }
   ///////////////////////////////////////////////////
   // # class Vector2D:
   // Represents a 2 element vector
   CSG.Vector2D = function (x, y) {
     if (arguments.length === 2) {
       this._x = parseFloat(x)
       this._y = parseFloat(y)
     } else {
       var ok = true
       if (arguments.length === 1) {
         if (typeof (x) === "object") {
           if (x instanceof CSG.Vector2D) {
             this._x = x._x
             this._y = x._y
           } else if (x instanceof Array) {
             this._x = parseFloat(x[0])
             this._y = parseFloat(x[1])
           } else if (('x' in x) && ('y' in x)) {
             this._x = parseFloat(x.x)
             this._y = parseFloat(x.y)
           } else ok = false
         } else {
           var v = parseFloat(x)
           this._x = v
           this._y = v
         }
       } else ok = false
       if (ok) {
         if ((!CSG.IsFloat(this._x)) || (!CSG.IsFloat(this._y))) ok = false
       }
       if (!ok) {
         throw new Error("wrong arguments")
       }
     }
   }
   CSG.Vector2D.fromAngle = function (radians) {
     return CSG.Vector2D.fromAngleRadians(radians)
   }
   CSG.Vector2D.fromAngleDegrees = function (degrees) {
     var radians = Math.PI * degrees / 180
     return CSG.Vector2D.fromAngleRadians(radians)
   }
   CSG.Vector2D.fromAngleRadians = function (radians) {
     return CSG.Vector2D.Create(Math.cos(radians), Math.sin(radians))
   }
   // This does the same as new CSG.Vector2D(x,y) but it doesn't go through the constructor
   // and the parameters are not validated. Is much faster.
   CSG.Vector2D.Create = function (x, y) {
     var result = Object.create(CSG.Vector2D.prototype)
     result._x = x
     result._y = y
     return result
   }
   CSG.Vector2D.prototype = {
     get x() {
       return this._x
     },
     get y() {
       return this._y
     },
     set x(v) {
       throw new Error("Vector2D is immutable")
     },
     set y(v) {
       throw new Error("Vector2D is immutable")
     },
     // extend to a 3D vector by adding a z coordinate:
     toVector3D: function (z) {
       return new CSG.Vector3D(this._x, this._y, z)
     },
     equals: function (a) {
       return (this._x === a._x) && (this._y === a._y)
     },
     clone: function () {
       return CSG.Vector2D.Create(this._x, this._y)
     },
     negated: function () {
       return CSG.Vector2D.Create(-this._x, -this._y)
     },
     plus: function (a) {
       return CSG.Vector2D.Create(this._x + a._x, this._y + a._y)
     },
     minus: function (a) {
       return CSG.Vector2D.Create(this._x - a._x, this._y - a._y)
     },
     times: function (a) {
       return CSG.Vector2D.Create(this._x * a, this._y * a)
     },
     dividedBy: function (a) {
       return CSG.Vector2D.Create(this._x / a, this._y / a)
     },
     dot: function (a) {
       return this._x * a._x + this._y * a._y
     },
     lerp: function (a, t) {
       return this.plus(a.minus(this).times(t))
     },
     length: function () {
       return Math.sqrt(this.dot(this))
     },
     distanceTo: function (a) {
       return this.minus(a).length()
     },
     distanceToSquared: function (a) {
       return this.minus(a).lengthSquared()
     },
     lengthSquared: function () {
       return this.dot(this)
     },
     unit: function () {
       return this.dividedBy(this.length())
     },
     cross: function (a) {
       return this._x * a._y - this._y * a._x
     },
     // returns the vector rotated by 90 degrees clockwise
     normal: function () {
       return CSG.Vector2D.Create(this._y, -this._x)
     },
     // Right multiply by a 4x4 matrix (the vector is interpreted as a row vector)
     // Returns a new CSG.Vector2D
     multiply4x4: function (matrix4x4) {
       return matrix4x4.leftMultiply1x2Vector(this)
     },
     transform: function (matrix4x4) {
       return matrix4x4.leftMultiply1x2Vector(this)
     },
     angle: function () {
       return this.angleRadians()
     },
     angleDegrees: function () {
       var radians = this.angleRadians()
       return 180 * radians / Math.PI
     },
     angleRadians: function () {
       // y=sin, x=cos
       return Math.atan2(this._y, this._x)
     },
     min: function (p) {
       return CSG.Vector2D.Create(
         Math.min(this._x, p._x), Math.min(this._y, p._y))
     },
     max: function (p) {
       return CSG.Vector2D.Create(
         Math.max(this._x, p._x), Math.max(this._y, p._y))
     },
     toString: function () {
       return "(" + this._x.toFixed(2) + ", " + this._y.toFixed(2) + ")"
     },
     abs: function () {
       return CSG.Vector2D.Create(Math.abs(this._x), Math.abs(this._y))
     },
   }
   // # class Line2D
   // Represents a directional line in 2D space
   // A line is parametrized by its normal vector (perpendicular to the line, rotated 90 degrees counter clockwise)
   // and w. The line passes through the point <normal>.times(w).
   // normal must be a unit vector!
   // Equation: p is on line if normal.dot(p)==w
   CSG.Line2D = function (normal, w) {
     normal = new CSG.Vector2D(normal)
     w = parseFloat(w)
     var l = normal.length()
       // normalize:
     w *= l
     normal = normal.times(1.0 / l)
     this.normal = normal
     this.w = w
   }
   CSG.Line2D.fromPoints = function (p1, p2) {
     p1 = new CSG.Vector2D(p1)
     p2 = new CSG.Vector2D(p2)
     var direction = p2.minus(p1)
     var normal = direction.normal().negated().unit()
     var w = p1.dot(normal)
     return new CSG.Line2D(normal, w)
   }
   CSG.Line2D.prototype = {
     // same line but opposite direction:
     reverse: function () {
       return new CSG.Line2D(this.normal.negated(), -this.w)
     },
     equals: function (l) {
       return (l.normal.equals(this.normal) && (l.w === this.w))
     },
     origin: function () {
       return this.normal.times(this.w)
     },
     direction: function () {
       return this.normal.normal()
     },
     xAtY: function (y) {
       // (py === y) && (normal * p === w)
       // -> px = (w - normal._y * y) / normal.x
       var x = (this.w - this.normal._y * y) / this.normal.x
       return x
     },
     absDistanceToPoint: function (point) {
       point = new CSG.Vector2D(point)
       var point_projected = point.dot(this.normal)
       var distance = Math.abs(point_projected - this.w)
       return distance
     },
     /*FIXME: has error - origin is not defined, the method is never used
      closestPoint: function(point) {
          point = new CSG.Vector2D(point);
          var vector = point.dot(this.direction());
          return origin.plus(vector);
      },
      */
     // intersection between two lines, returns point as Vector2D
     intersectWithLine: function (line2d) {
       var point = CSG.solve2Linear(this.normal.x, this.normal.y, line2d.normal.x, line2d.normal.y, this.w, line2d.w)
       point = new CSG.Vector2D(point) // make  vector2d
       return point
     },
     transform: function (matrix4x4) {
       var origin = new CSG.Vector2D(0, 0)
       var pointOnPlane = this.normal.times(this.w)
       var neworigin = origin.multiply4x4(matrix4x4)
       var neworiginPlusNormal = this.normal.multiply4x4(matrix4x4)
       var newnormal = neworiginPlusNormal.minus(neworigin)
       var newpointOnPlane = pointOnPlane.multiply4x4(matrix4x4)
       var neww = newnormal.dot(newpointOnPlane)
       return new CSG.Line2D(newnormal, neww)
     }
   }
   // # class Line3D
   // Represents a line in 3D space
   // direction must be a unit vector
   // point is a random point on the line
   CSG.Line3D = function (point, direction) {
     point = new CSG.Vector3D(point)
     direction = new CSG.Vector3D(direction)
     this.point = point
     this.direction = direction.unit()
   }
   CSG.Line3D.fromPoints = function (p1, p2) {
     p1 = new CSG.Vector3D(p1)
     p2 = new CSG.Vector3D(p2)
     var direction = p2.minus(p1)
     return new CSG.Line3D(p1, direction)
   }
   CSG.Line3D.fromPlanes = function (p1, p2) {
     var direction = p1.normal.cross(p2.normal)
     var l = direction.length()
     if (l < 1e-10) {
       throw new Error("Parallel planes")
     }
     direction = direction.times(1.0 / l)
     var mabsx = Math.abs(direction.x)
     var mabsy = Math.abs(direction.y)
     var mabsz = Math.abs(direction.z)
     var origin
     if ((mabsx >= mabsy) && (mabsx >= mabsz)) {
       // direction vector is mostly pointing towards x
       // find a point p for which x is zero:
       var r = CSG.solve2Linear(p1.normal.y, p1.normal.z, p2.normal.y, p2.normal.z, p1.w, p2.w)
       origin = new CSG.Vector3D(0, r[0], r[1])
     } else if ((mabsy >= mabsx) && (mabsy >= mabsz)) {
       // find a point p for which y is zero:
       var r = CSG.solve2Linear(p1.normal.x, p1.normal.z, p2.normal.x, p2.normal.z, p1.w, p2.w)
       origin = new CSG.Vector3D(r[0], 0, r[1])
     } else {
       // find a point p for which z is zero:
       var r = CSG.solve2Linear(p1.normal.x, p1.normal.y, p2.normal.x, p2.normal.y, p1.w, p2.w)
       origin = new CSG.Vector3D(r[0], r[1], 0)
     }
     return new CSG.Line3D(origin, direction)
   }
   CSG.Line3D.prototype = {
     intersectWithPlane: function (plane) {
       // plane: plane.normal * p = plane.w
       // line: p=line.point + labda * line.direction
       var labda = (plane.w - plane.normal.dot(this.point)) / plane.normal.dot(this.direction)
       var point = this.point.plus(this.direction.times(labda))
       return point
     },
     clone: function (line) {
       return new CSG.Line3D(this.point.clone(), this.direction.clone())
     },
     reverse: function () {
       return new CSG.Line3D(this.point.clone(), this.direction.negated())
     },
     transform: function (matrix4x4) {
       var newpoint = this.point.multiply4x4(matrix4x4)
       var pointPlusDirection = this.point.plus(this.direction)
       var newPointPlusDirection = pointPlusDirection.multiply4x4(matrix4x4)
       var newdirection = newPointPlusDirection.minus(newpoint)
       return new CSG.Line3D(newpoint, newdirection)
     },
     closestPointOnLine: function (point) {
       point = new CSG.Vector3D(point)
       var t = point.minus(this.point).dot(this.direction) / this.direction.dot(this.direction)
       var closestpoint = this.point.plus(this.direction.times(t))
       return closestpoint
     },
     distanceToPoint: function (point) {
       point = new CSG.Vector3D(point)
       var closestpoint = this.closestPointOnLine(point)
       var distancevector = point.minus(closestpoint)
       var distance = distancevector.length()
       return distance
     },
     equals: function (line3d) {
       if (!this.direction.equals(line3d.direction)) return false
       var distance = this.distanceToPoint(line3d.point)
       if (distance > 1e-8) return false
       return true
     }
   }
   // # class OrthoNormalBasis
   // Reprojects points on a 3D plane onto a 2D plane
   // or from a 2D plane back onto the 3D plane
   CSG.OrthoNormalBasis = function (plane, rightvector) {
     if (arguments.length < 2) {
       // choose an arbitrary right hand vector, making sure it is somewhat orthogonal to the plane normal:
       rightvector = plane.normal.randomNonParallelVector()
     } else {
       rightvector = new CSG.Vector3D(rightvector)
     }
     this.v = plane.normal.cross(rightvector).unit()
     this.u = this.v.cross(plane.normal)
     this.plane = plane
     this.planeorigin = plane.normal.times(plane.w)
   }
   // Get an orthonormal basis for the standard XYZ planes.
   // Parameters: the names of two 3D axes. The 2d x axis will map to the first given 3D axis, the 2d y 
   // axis will map to the second.
   // Prepend the axis with a "-" to invert the direction of this axis.
   // For example: CSG.OrthoNormalBasis.GetCartesian("-Y","Z")
   //   will return an orthonormal basis where the 2d X axis maps to the 3D inverted Y axis, and
   //   the 2d Y axis maps to the 3D Z axis.
   CSG.OrthoNormalBasis.GetCartesian = function (xaxisid, yaxisid) {
     var axisid = xaxisid + "/" + yaxisid
     var planenormal, rightvector
     if (axisid === "X/Y") {
       planenormal = [0, 0, 1]
       rightvector = [1, 0, 0]
     } else if (axisid === "Y/-X") {
       planenormal = [0, 0, 1]
       rightvector = [0, 1, 0]
     } else if (axisid === "-X/-Y") {
       planenormal = [0, 0, 1]
       rightvector = [-1, 0, 0]
     } else if (axisid === "-Y/X") {
       planenormal = [0, 0, 1]
       rightvector = [0, -1, 0]
     } else if (axisid === "-X/Y") {
       planenormal = [0, 0, -1]
       rightvector = [-1, 0, 0]
     } else if (axisid === "-Y/-X") {
       planenormal = [0, 0, -1]
       rightvector = [0, -1, 0]
     } else if (axisid === "X/-Y") {
       planenormal = [0, 0, -1]
       rightvector = [1, 0, 0]
     } else if (axisid === "Y/X") {
       planenormal = [0, 0, -1]
       rightvector = [0, 1, 0]
     } else if (axisid === "X/Z") {
       planenormal = [0, -1, 0]
       rightvector = [1, 0, 0]
     } else if (axisid === "Z/-X") {
       planenormal = [0, -1, 0]
       rightvector = [0, 0, 1]
     } else if (axisid === "-X/-Z") {
       planenormal = [0, -1, 0]
       rightvector = [-1, 0, 0]
     } else if (axisid === "-Z/X") {
       planenormal = [0, -1, 0]
       rightvector = [0, 0, -1]
     } else if (axisid === "-X/Z") {
       planenormal = [0, 1, 0]
       rightvector = [-1, 0, 0]
     } else if (axisid === "-Z/-X") {
       planenormal = [0, 1, 0]
       rightvector = [0, 0, -1]
     } else if (axisid === "X/-Z") {
       planenormal = [0, 1, 0]
       rightvector = [1, 0, 0]
     } else if (axisid === "Z/X") {
       planenormal = [0, 1, 0]
       rightvector = [0, 0, 1]
     } else if (axisid === "Y/Z") {
       planenormal = [1, 0, 0]
       rightvector = [0, 1, 0]
     } else if (axisid === "Z/-Y") {
       planenormal = [1, 0, 0]
       rightvector = [0, 0, 1]
     } else if (axisid === "-Y/-Z") {
       planenormal = [1, 0, 0]
       rightvector = [0, -1, 0]
     } else if (axisid === "-Z/Y") {
       planenormal = [1, 0, 0]
       rightvector = [0, 0, -1]
     } else if (axisid === "-Y/Z") {
       planenormal = [-1, 0, 0]
       rightvector = [0, -1, 0]
     } else if (axisid === "-Z/-Y") {
       planenormal = [-1, 0, 0]
       rightvector = [0, 0, -1]
     } else if (axisid === "Y/-Z") {
       planenormal = [-1, 0, 0]
       rightvector = [0, 1, 0]
     } else if (axisid === "Z/Y") {
       planenormal = [-1, 0, 0]
       rightvector = [0, 0, 1]
     } else {
       throw new Error("CSG.OrthoNormalBasis.GetCartesian: invalid combination of axis identifiers. Should pass two string arguments from [X,Y,Z,-X,-Y,-Z], being two different axes.")
     }
     return new CSG.OrthoNormalBasis(new CSG.Plane(new CSG.Vector3D(planenormal), 0), new CSG.Vector3D(rightvector))
   }
   /*
   // test code for CSG.OrthoNormalBasis.GetCartesian()
   CSG.OrthoNormalBasis.GetCartesian_Test=function() {
     var axisnames=["X","Y","Z","-X","-Y","-Z"];
     var axisvectors=[[1,0,0], [0,1,0], [0,0,1], [-1,0,0], [0,-1,0], [0,0,-1]];
     for(var axis1=0; axis1 < 3; axis1++) {
       for(var axis1inverted=0; axis1inverted < 2; axis1inverted++) {
         var axis1name=axisnames[axis1+3*axis1inverted];
         var axis1vector=axisvectors[axis1+3*axis1inverted];
         for(var axis2=0; axis2 < 3; axis2++) {
           if(axis2 !== axis1) {
             for(var axis2inverted=0; axis2inverted < 2; axis2inverted++) {
               var axis2name=axisnames[axis2+3*axis2inverted];
               var axis2vector=axisvectors[axis2+3*axis2inverted];
               var orthobasis=CSG.OrthoNormalBasis.GetCartesian(axis1name, axis2name);
               var test1=orthobasis.to3D(new CSG.Vector2D([1,0]));
               var test2=orthobasis.to3D(new CSG.Vector2D([0,1]));
               var expected1=new CSG.Vector3D(axis1vector);
               var expected2=new CSG.Vector3D(axis2vector);
               var d1=test1.distanceTo(expected1);
               var d2=test2.distanceTo(expected2);
               if( (d1 > 0.01) || (d2 > 0.01) ) {
                 throw new Error("Wrong!");
     }}}}}}
     throw new Error("OK");
   };
   */
   // The z=0 plane, with the 3D x and y vectors mapped to the 2D x and y vector
   CSG.OrthoNormalBasis.Z0Plane = function () {
     var plane = new CSG.Plane(new CSG.Vector3D([0, 0, 1]), 0)
     return new CSG.OrthoNormalBasis(plane, new CSG.Vector3D([1, 0, 0]))
   }
   CSG.OrthoNormalBasis.prototype = {
     getProjectionMatrix: function () {
       return new CSG.Matrix4x4([
         this.u.x, this.v.x, this.plane.normal.x, 0,
         this.u.y, this.v.y, this.plane.normal.y, 0,
         this.u.z, this.v.z, this.plane.normal.z, 0,
         0, 0, -this.plane.w, 1
       ])
     },
     getInverseProjectionMatrix: function () {
       var p = this.plane.normal.times(this.plane.w)
       return new CSG.Matrix4x4([
         this.u.x, this.u.y, this.u.z, 0,
         this.v.x, this.v.y, this.v.z, 0,
         this.plane.normal.x, this.plane.normal.y, this.plane.normal.z, 0,
         p.x, p.y, p.z, 1
       ])
     },
     to2D: function (vec3) {
       return new CSG.Vector2D(vec3.dot(this.u), vec3.dot(this.v))
     },
     to3D: function (vec2) {
       return this.planeorigin.plus(this.u.times(vec2.x)).plus(this.v.times(vec2.y))
     },
     line3Dto2D: function (line3d) {
       var a = line3d.point
       var b = line3d.direction.plus(a)
       var a2d = this.to2D(a)
       var b2d = this.to2D(b)
       return CSG.Line2D.fromPoints(a2d, b2d)
     },
     line2Dto3D: function (line2d) {
       var a = line2d.origin()
       var b = line2d.direction().plus(a)
       var a3d = this.to3D(a)
       var b3d = this.to3D(b)
       return CSG.Line3D.fromPoints(a3d, b3d)
     },
     transform: function (matrix4x4) {
       // todo: this may not work properly in case of mirroring
       var newplane = this.plane.transform(matrix4x4)
       var rightpoint_transformed = this.u.transform(matrix4x4)
       var origin_transformed = new CSG.Vector3D(0, 0, 0).transform(matrix4x4)
       var newrighthandvector = rightpoint_transformed.minus(origin_transformed)
       var newbasis = new CSG.OrthoNormalBasis(newplane, newrighthandvector)
       return newbasis
     }
   }

   function insertSorted(array, element, comparefunc) {
     var leftbound = 0
     var rightbound = array.length
     while (rightbound > leftbound) {
       var testindex = Math.floor((leftbound + rightbound) / 2)
       var testelement = array[testindex]
       var compareresult = comparefunc(element, testelement)
       if (compareresult > 0) // element > testelement
       {
         leftbound = testindex + 1
       } else {
         rightbound = testindex
       }
     }
     array.splice(leftbound, 0, element)
   }
   // Get the x coordinate of a point with a certain y coordinate, interpolated between two
   // points (CSG.Vector2D).
   // Interpolation is robust even if the points have the same y coordinate
   CSG.interpolateBetween2DPointsForY = function (point1, point2, y) {
     var f1 = y - point1.y
     var f2 = point2.y - point1.y
     if (f2 < 0) {
       f1 = -f1
       f2 = -f2
     }
     var t
     if (f1 <= 0) {
       t = 0.0
     } else if (f1 >= f2) {
       t = 1.0
     } else if (f2 < 1e-10) {
       t = 0.5
     } else {
       t = f1 / f2
     }
     var result = point1.x + t * (point2.x - point1.x)
     return result
   }
   // Retesselation function for a set of coplanar polygons. See the introduction at the top of
   // this file.
   CSG.reTesselateCoplanarPolygons = function (sourcepolygons, destpolygons) {
       var EPS = 1e-5
       var numpolygons = sourcepolygons.length
       if (numpolygons > 0) {
         var plane = sourcepolygons[0].plane
         var shared = sourcepolygons[0].shared
         var orthobasis = new CSG.OrthoNormalBasis(plane)
         var polygonvertices2d = [] // array of array of CSG.Vector2D
         var polygontopvertexindexes = [] // array of indexes of topmost vertex per polygon
         var topy2polygonindexes = {}
         var ycoordinatetopolygonindexes = {}
         var xcoordinatebins = {}
         var ycoordinatebins = {}
           // convert all polygon vertices to 2D
           // Make a list of all encountered y coordinates
           // And build a map of all polygons that have a vertex at a certain y coordinate:
         var ycoordinateBinningFactor = 1.0 / EPS * 10
         for (var polygonindex = 0; polygonindex < numpolygons; polygonindex++) {
           var poly3d = sourcepolygons[polygonindex]
           var vertices2d = []
           var numvertices = poly3d.vertices.length
           var minindex = -1
           if (numvertices > 0) {
             var miny, maxy, maxindex
             for (var i = 0; i < numvertices; i++) {
               var pos2d = orthobasis.to2D(poly3d.vertices[i].pos)
                 // perform binning of y coordinates: If we have multiple vertices very
                 // close to each other, give them the same y coordinate:
               var ycoordinatebin = Math.floor(pos2d.y * ycoordinateBinningFactor)
               var newy
               if (ycoordinatebin in ycoordinatebins) {
                 newy = ycoordinatebins[ycoordinatebin]
               } else if (ycoordinatebin + 1 in ycoordinatebins) {
                 newy = ycoordinatebins[ycoordinatebin + 1]
               } else if (ycoordinatebin - 1 in ycoordinatebins) {
                 newy = ycoordinatebins[ycoordinatebin - 1]
               } else {
                 newy = pos2d.y
                 ycoordinatebins[ycoordinatebin] = pos2d.y
               }
               pos2d = CSG.Vector2D.Create(pos2d.x, newy)
               vertices2d.push(pos2d)
               var y = pos2d.y
               if ((i === 0) || (y < miny)) {
                 miny = y
                 minindex = i
               }
               if ((i === 0) || (y > maxy)) {
                 maxy = y
                 maxindex = i
               }
               if (!(y in ycoordinatetopolygonindexes)) {
                 ycoordinatetopolygonindexes[y] = {}
               }
               ycoordinatetopolygonindexes[y][polygonindex] = true
             }
             if (miny >= maxy) {
               // degenerate polygon, all vertices have same y coordinate. Just ignore it from now:
               vertices2d = []
               numvertices = 0
               minindex = -1
             } else {
               if (!(miny in topy2polygonindexes)) {
                 topy2polygonindexes[miny] = []
               }
               topy2polygonindexes[miny].push(polygonindex)
             }
           } // if(numvertices > 0)
           // reverse the vertex order:
           vertices2d.reverse()
           minindex = numvertices - minindex - 1
           polygonvertices2d.push(vertices2d)
           polygontopvertexindexes.push(minindex)
         }
         var ycoordinates = []
         for (var ycoordinate in ycoordinatetopolygonindexes) ycoordinates.push(ycoordinate)
         ycoordinates.sort(fnNumberSort)
           // Now we will iterate over all y coordinates, from lowest to highest y coordinate
           // activepolygons: source polygons that are 'active', i.e. intersect with our y coordinate
           //   Is sorted so the polygons are in left to right order
           // Each element in activepolygons has these properties:
           //        polygonindex: the index of the source polygon (i.e. an index into the sourcepolygons
           //                      and polygonvertices2d arrays)
           //        leftvertexindex: the index of the vertex at the left side of the polygon (lowest x)
           //                         that is at or just above the current y coordinate
           //        rightvertexindex: dito at right hand side of polygon
           //        topleft, bottomleft: coordinates of the left side of the polygon crossing the current y coordinate
           //        topright, bottomright: coordinates of the right hand side of the polygon crossing the current y coordinate
         var activepolygons = []
         var prevoutpolygonrow = []
         for (var yindex = 0; yindex < ycoordinates.length; yindex++) {
           var newoutpolygonrow = []
           var ycoordinate_as_string = ycoordinates[yindex]
           var ycoordinate = Number(ycoordinate_as_string)
             // update activepolygons for this y coordinate:
             // - Remove any polygons that end at this y coordinate
             // - update leftvertexindex and rightvertexindex (which point to the current vertex index
             //   at the the left and right side of the polygon
             // Iterate over all polygons that have a corner at this y coordinate:
           var polygonindexeswithcorner = ycoordinatetopolygonindexes[ycoordinate_as_string]
           for (var activepolygonindex = 0; activepolygonindex < activepolygons.length; ++activepolygonindex) {
             var activepolygon = activepolygons[activepolygonindex]
             var polygonindex = activepolygon.polygonindex
             if (polygonindexeswithcorner[polygonindex]) {
               // this active polygon has a corner at this y coordinate:
               var vertices2d = polygonvertices2d[polygonindex]
               var numvertices = vertices2d.length
               var newleftvertexindex = activepolygon.leftvertexindex
               var newrightvertexindex = activepolygon.rightvertexindex
                 // See if we need to increase leftvertexindex or decrease rightvertexindex:
               while (true) {
                 var nextleftvertexindex = newleftvertexindex + 1
                 if (nextleftvertexindex >= numvertices) nextleftvertexindex = 0
                 if (vertices2d[nextleftvertexindex].y !== ycoordinate) break
                 newleftvertexindex = nextleftvertexindex
               }
               var nextrightvertexindex = newrightvertexindex - 1
               if (nextrightvertexindex < 0) nextrightvertexindex = numvertices - 1
               if (vertices2d[nextrightvertexindex].y === ycoordinate) {
                 newrightvertexindex = nextrightvertexindex
               }
               if ((newleftvertexindex !== activepolygon.leftvertexindex) && (newleftvertexindex === newrightvertexindex)) {
                 // We have increased leftvertexindex or decreased rightvertexindex, and now they point to the same vertex
                 // This means that this is the bottom point of the polygon. We'll remove it:
                 activepolygons.splice(activepolygonindex, 1);
                 --activepolygonindex
               } else {
                 activepolygon.leftvertexindex = newleftvertexindex
                 activepolygon.rightvertexindex = newrightvertexindex
                 activepolygon.topleft = vertices2d[newleftvertexindex]
                 activepolygon.topright = vertices2d[newrightvertexindex]
                 var nextleftvertexindex = newleftvertexindex + 1
                 if (nextleftvertexindex >= numvertices) nextleftvertexindex = 0
                 activepolygon.bottomleft = vertices2d[nextleftvertexindex]
                 var nextrightvertexindex = newrightvertexindex - 1
                 if (nextrightvertexindex < 0) nextrightvertexindex = numvertices - 1
                 activepolygon.bottomright = vertices2d[nextrightvertexindex]
               }
             } // if polygon has corner here
           } // for activepolygonindex
           var nextycoordinate
           if (yindex >= ycoordinates.length - 1) {
             // last row, all polygons must be finished here:
             activepolygons = []
             nextycoordinate = null
           } else // yindex < ycoordinates.length-1
           {
             nextycoordinate = Number(ycoordinates[yindex + 1])
             var middleycoordinate = 0.5 * (ycoordinate + nextycoordinate)
               // update activepolygons by adding any polygons that start here:
             var startingpolygonindexes = topy2polygonindexes[ycoordinate_as_string]
             for (var polygonindex_key in startingpolygonindexes) {
               var polygonindex = startingpolygonindexes[polygonindex_key]
               var vertices2d = polygonvertices2d[polygonindex]
               var numvertices = vertices2d.length
               var topvertexindex = polygontopvertexindexes[polygonindex]
                 // the top of the polygon may be a horizontal line. In that case topvertexindex can point to any point on this line.
                 // Find the left and right topmost vertices which have the current y coordinate:
               var topleftvertexindex = topvertexindex
               while (true) {
                 var i = topleftvertexindex + 1
                 if (i >= numvertices) i = 0
                 if (vertices2d[i].y !== ycoordinate) break
                 if (i === topvertexindex) break // should not happen, but just to prevent endless loops
                 topleftvertexindex = i
               }
               var toprightvertexindex = topvertexindex
               while (true) {
                 var i = toprightvertexindex - 1
                 if (i < 0) i = numvertices - 1
                 if (vertices2d[i].y !== ycoordinate) break
                 if (i === topleftvertexindex) break // should not happen, but just to prevent endless loops
                 toprightvertexindex = i
               }
               var nextleftvertexindex = topleftvertexindex + 1
               if (nextleftvertexindex >= numvertices) nextleftvertexindex = 0
               var nextrightvertexindex = toprightvertexindex - 1
               if (nextrightvertexindex < 0) nextrightvertexindex = numvertices - 1
               var newactivepolygon = {
                 polygonindex: polygonindex,
                 leftvertexindex: topleftvertexindex,
                 rightvertexindex: toprightvertexindex,
                 topleft: vertices2d[topleftvertexindex],
                 topright: vertices2d[toprightvertexindex],
                 bottomleft: vertices2d[nextleftvertexindex],
                 bottomright: vertices2d[nextrightvertexindex],
               }
               insertSorted(activepolygons, newactivepolygon, function (el1, el2) {
                 var x1 = CSG.interpolateBetween2DPointsForY(
                   el1.topleft, el1.bottomleft, middleycoordinate)
                 var x2 = CSG.interpolateBetween2DPointsForY(
                   el2.topleft, el2.bottomleft, middleycoordinate)
                 if (x1 > x2) return 1
                 if (x1 < x2) return -1
                 return 0
               })
             } // for(var polygonindex in startingpolygonindexes)
           } //  yindex < ycoordinates.length-1
           //if( (yindex === ycoordinates.length-1) || (nextycoordinate - ycoordinate > EPS) )
           if (true) {
             // Now activepolygons is up to date
             // Build the output polygons for the next row in newoutpolygonrow:
             for (var activepolygon_key in activepolygons) {
               var activepolygon = activepolygons[activepolygon_key]
               var polygonindex = activepolygon.polygonindex
               var vertices2d = polygonvertices2d[polygonindex]
               var numvertices = vertices2d.length
               var x = CSG.interpolateBetween2DPointsForY(activepolygon.topleft, activepolygon.bottomleft, ycoordinate)
               var topleft = CSG.Vector2D.Create(x, ycoordinate)
               x = CSG.interpolateBetween2DPointsForY(activepolygon.topright, activepolygon.bottomright, ycoordinate)
               var topright = CSG.Vector2D.Create(x, ycoordinate)
               x = CSG.interpolateBetween2DPointsForY(activepolygon.topleft, activepolygon.bottomleft, nextycoordinate)
               var bottomleft = CSG.Vector2D.Create(x, nextycoordinate)
               x = CSG.interpolateBetween2DPointsForY(activepolygon.topright, activepolygon.bottomright, nextycoordinate)
               var bottomright = CSG.Vector2D.Create(x, nextycoordinate)
               var outpolygon = {
                 topleft: topleft,
                 topright: topright,
                 bottomleft: bottomleft,
                 bottomright: bottomright,
                 leftline: CSG.Line2D.fromPoints(topleft, bottomleft),
                 rightline: CSG.Line2D.fromPoints(bottomright, topright)
               }
               if (newoutpolygonrow.length > 0) {
                 var prevoutpolygon = newoutpolygonrow[newoutpolygonrow.length - 1]
                 var d1 = outpolygon.topleft.distanceTo(prevoutpolygon.topright)
                 var d2 = outpolygon.bottomleft.distanceTo(prevoutpolygon.bottomright)
                 if ((d1 < EPS) && (d2 < EPS)) {
                   // we can join this polygon with the one to the left:
                   outpolygon.topleft = prevoutpolygon.topleft
                   outpolygon.leftline = prevoutpolygon.leftline
                   outpolygon.bottomleft = prevoutpolygon.bottomleft
                   newoutpolygonrow.splice(newoutpolygonrow.length - 1, 1)
                 }
               }
               newoutpolygonrow.push(outpolygon)
             } // for(activepolygon in activepolygons)
             if (yindex > 0) {
               // try to match the new polygons against the previous row:
               var prevcontinuedindexes = {}
               var matchedindexes = {}
               for (var i = 0; i < newoutpolygonrow.length; i++) {
                 var thispolygon = newoutpolygonrow[i]
                 for (var ii = 0; ii < prevoutpolygonrow.length; ii++) {
                   if (!matchedindexes[ii]) // not already processed?
                   {
                     // We have a match if the sidelines are equal or if the top coordinates
                     // are on the sidelines of the previous polygon
                     var prevpolygon = prevoutpolygonrow[ii]
                     if (prevpolygon.bottomleft.distanceTo(thispolygon.topleft) < EPS) {
                       if (prevpolygon.bottomright.distanceTo(thispolygon.topright) < EPS) {
                         // Yes, the top of this polygon matches the bottom of the previous:
                         matchedindexes[ii] = true
                           // Now check if the joined polygon would remain convex:
                         var d1 = thispolygon.leftline.direction().x - prevpolygon.leftline.direction().x
                         var d2 = thispolygon.rightline.direction().x - prevpolygon.rightline.direction().x
                         var leftlinecontinues = Math.abs(d1) < EPS
                         var rightlinecontinues = Math.abs(d2) < EPS
                         var leftlineisconvex = leftlinecontinues || (d1 >= 0)
                         var rightlineisconvex = rightlinecontinues || (d2 >= 0)
                         if (leftlineisconvex && rightlineisconvex) {
                           // yes, both sides have convex corners:
                           // This polygon will continue the previous polygon
                           thispolygon.outpolygon = prevpolygon.outpolygon
                           thispolygon.leftlinecontinues = leftlinecontinues
                           thispolygon.rightlinecontinues = rightlinecontinues
                           prevcontinuedindexes[ii] = true
                         }
                         break
                       }
                     }
                   } // if(!prevcontinuedindexes[ii])
                 } // for ii
               } // for i
               for (var ii = 0; ii < prevoutpolygonrow.length; ii++) {
                 if (!prevcontinuedindexes[ii]) {
                   // polygon ends here
                   // Finish the polygon with the last point(s):
                   var prevpolygon = prevoutpolygonrow[ii]
                   prevpolygon.outpolygon.rightpoints.push(prevpolygon.bottomright)
                   if (prevpolygon.bottomright.distanceTo(prevpolygon.bottomleft) > EPS) {
                     // polygon ends with a horizontal line:
                     prevpolygon.outpolygon.leftpoints.push(prevpolygon.bottomleft)
                   }
                   // reverse the left half so we get a counterclockwise circle:
                   prevpolygon.outpolygon.leftpoints.reverse()
                   var points2d = prevpolygon.outpolygon.rightpoints.concat(prevpolygon.outpolygon.leftpoints)
                   var vertices3d = []
                   points2d.map(function (point2d) {
                     var point3d = orthobasis.to3D(point2d)
                     var vertex3d = new CSG.Vertex(point3d)
                     vertices3d.push(vertex3d)
                   })
                   var polygon = new CSG.Polygon(vertices3d, shared, plane)
                   destpolygons.push(polygon)
                 }
               }
             } // if(yindex > 0)
             for (var i = 0; i < newoutpolygonrow.length; i++) {
               var thispolygon = newoutpolygonrow[i]
               if (!thispolygon.outpolygon) {
                 // polygon starts here:
                 thispolygon.outpolygon = {
                   leftpoints: [],
                   rightpoints: []
                 }
                 thispolygon.outpolygon.leftpoints.push(thispolygon.topleft)
                 if (thispolygon.topleft.distanceTo(thispolygon.topright) > EPS) {
                   // we have a horizontal line at the top:
                   thispolygon.outpolygon.rightpoints.push(thispolygon.topright)
                 }
               } else {
                 // continuation of a previous row
                 if (!thispolygon.leftlinecontinues) {
                   thispolygon.outpolygon.leftpoints.push(thispolygon.topleft)
                 }
                 if (!thispolygon.rightlinecontinues) {
                   thispolygon.outpolygon.rightpoints.push(thispolygon.topright)
                 }
               }
             }
             prevoutpolygonrow = newoutpolygonrow
           }
         } // for yindex
       } // if(numpolygons > 0)
     }
     ////////////////////////////////
     // ## class fuzzyFactory
     // This class acts as a factory for objects. We can search for an object with approximately
     // the desired properties (say a rectangle with width 2 and height 1)
     // The lookupOrCreate() method looks for an existing object (for example it may find an existing rectangle
     // with width 2.0001 and height 0.999. If no object is found, the user supplied callback is
     // called, which should generate a new object. The new object is inserted into the database
     // so it can be found by future lookupOrCreate() calls.
     // Constructor:
     //   numdimensions: the number of parameters for each object
     //     for example for a 2D rectangle this would be 2
     //   tolerance: The maximum difference for each parameter allowed to be considered a match
   CSG.fuzzyFactory = function (numdimensions, tolerance) {
     this.lookuptable = {}
     this.multiplier = 1.0 / tolerance
   }
   CSG.fuzzyFactory.prototype = {
       // var obj = f.lookupOrCreate([el1, el2, el3], function(elements) {/* create the new object */});
       // Performs a fuzzy lookup of the object with the specified elements.
       // If found, returns the existing object
       // If not found, calls the supplied callback function which should create a new object with
       // the specified properties. This object is inserted in the lookup database.
       lookupOrCreate: function (els, creatorCallback) {
         var hash = ""
         var multiplier = this.multiplier
         els.forEach(function (el) {
           var valueQuantized = Math.round(el * multiplier)
           hash += valueQuantized + "/"
         })
         if (hash in this.lookuptable) {
           return this.lookuptable[hash]
         } else {
           var object = creatorCallback(els)
           var hashparts = els.map(function (el) {
             var q0 = Math.floor(el * multiplier)
             var q1 = q0 + 1
             return ["" + q0 + "/", "" + q1 + "/"]
           })
           var numelements = els.length
           var numhashes = 1 << numelements
           for (var hashmask = 0; hashmask < numhashes; ++hashmask) {
             var hashmask_shifted = hashmask
             hash = ""
             hashparts.forEach(function (hashpart) {
               hash += hashpart[hashmask_shifted & 1]
               hashmask_shifted >>= 1
             })
             this.lookuptable[hash] = object
           }
           return object
         }
       },
     }
     //////////////////////////////////////
   CSG.fuzzyCSGFactory = function () {
     this.vertexfactory = new CSG.fuzzyFactory(3, 1e-5)
     this.planefactory = new CSG.fuzzyFactory(4, 1e-5)
     this.polygonsharedfactory = {}
   }
   CSG.fuzzyCSGFactory.prototype = {
       getPolygonShared: function (sourceshared) {
         var hash = sourceshared.getHash()
         if (hash in this.polygonsharedfactory) {
           return this.polygonsharedfactory[hash]
         } else {
           this.polygonsharedfactory[hash] = sourceshared
           return sourceshared
         }
       },
       getVertex: function (sourcevertex) {
         var elements = [sourcevertex.pos._x, sourcevertex.pos._y, sourcevertex.pos._z]
         var result = this.vertexfactory.lookupOrCreate(elements, function (els) {
           return sourcevertex
         })
         return result
       },
       getPlane: function (sourceplane) {
         var elements = [sourceplane.normal._x, sourceplane.normal._y, sourceplane.normal._z, sourceplane.w]
         var result = this.planefactory.lookupOrCreate(elements, function (els) {
           return sourceplane
         })
         return result
       },
       getPolygon: function (sourcepolygon) {
         var newplane = this.getPlane(sourcepolygon.plane)
         var newshared = this.getPolygonShared(sourcepolygon.shared)
         var _this = this
         var newvertices = sourcepolygon.vertices.map(function (vertex) {
             return _this.getVertex(vertex)
           })
           // two vertices that were originally very close may now have become
           // truly identical (referring to the same CSG.Vertex object).
           // Remove duplicate vertices:
         var newvertices_dedup = []
         if (newvertices.length > 0) {
           var prevvertextag = newvertices[newvertices.length - 1].getTag()
           newvertices.forEach(function (vertex) {
             var vertextag = vertex.getTag()
             if (vertextag !== prevvertextag) {
               newvertices_dedup.push(vertex)
             }
             prevvertextag = vertextag
           })
         }
         // If it's degenerate, remove all vertices:
         if (newvertices_dedup.length < 3) {
           newvertices_dedup = []
         }
         return new CSG.Polygon(newvertices_dedup, newshared, newplane)
       },
       getCSG: function (sourcecsg) {
         var _this = this
         var newpolygons = []
         sourcecsg.polygons.forEach(function (polygon) {
           var newpolygon = _this.getPolygon(polygon)
             // see getPolygon above: we may get a polygon with no vertices, discard it:
           if (newpolygon.vertices.length >= 3) {
             newpolygons.push(newpolygon)
           }
         })
         return CSG.fromPolygons(newpolygons)
       }
     }
     //////////////////////////////////////
     // Tag factory: we can request a unique tag through CSG.getTag()
   CSG.staticTag = 1
   CSG.getTag = function () {
       return CSG.staticTag++
     }
     //////////////////////////////////////
     // # Class Properties
     // This class is used to store properties of a solid
     // A property can for example be a CSG.Vertex, a CSG.Plane or a CSG.Line3D
     // Whenever an affine transform is applied to the CSG solid, all its properties are
     // transformed as well.
     // The properties can be stored in a complex nested structure (using arrays and objects)
   CSG.Properties = function () {}
   CSG.Properties.prototype = {
     _transform: function (matrix4x4) {
       var result = new CSG.Properties()
       CSG.Properties.transformObj(this, result, matrix4x4)
       return result
     },
     _merge: function (otherproperties) {
       var result = new CSG.Properties()
       CSG.Properties.cloneObj(this, result)
       CSG.Properties.addFrom(result, otherproperties)
       return result
     }
   }
   CSG.Properties.transformObj = function (source, result, matrix4x4) {
     for (var propertyname in source) {
       if (propertyname === "_transform") continue
       if (propertyname === "_merge") continue
       var propertyvalue = source[propertyname]
       var transformed = propertyvalue
       if (typeof (propertyvalue) === "object") {
         if (('transform' in propertyvalue) && (typeof (propertyvalue.transform) === "function")) {
           transformed = propertyvalue.transform(matrix4x4)
         } else if (propertyvalue instanceof Array) {
           transformed = []
           CSG.Properties.transformObj(propertyvalue, transformed, matrix4x4)
         } else if (propertyvalue instanceof CSG.Properties) {
           transformed = new CSG.Properties()
           CSG.Properties.transformObj(propertyvalue, transformed, matrix4x4)
         }
       }
       result[propertyname] = transformed
     }
   }
   CSG.Properties.cloneObj = function (source, result) {
     for (var propertyname in source) {
       if (propertyname === "_transform") continue
       if (propertyname === "_merge") continue
       var propertyvalue = source[propertyname]
       var cloned = propertyvalue
       if (typeof (propertyvalue) === "object") {
         if (propertyvalue instanceof Array) {
           cloned = []
           for (var i = 0; i < propertyvalue.length; i++) {
             cloned.push(propertyvalue[i])
           }
         } else if (propertyvalue instanceof CSG.Properties) {
           cloned = new CSG.Properties()
           CSG.Properties.cloneObj(propertyvalue, cloned)
         }
       }
       result[propertyname] = cloned
     }
   }
   CSG.Properties.addFrom = function (result, otherproperties) {
       for (var propertyname in otherproperties) {
         if (propertyname === "_transform") continue
         if (propertyname === "_merge") continue
         if ((propertyname in result) &&
           (typeof (result[propertyname]) === "object") &&
           (result[propertyname] instanceof CSG.Properties) &&
           (typeof (otherproperties[propertyname]) === "object") &&
           (otherproperties[propertyname] instanceof CSG.Properties)) {
           CSG.Properties.addFrom(result[propertyname], otherproperties[propertyname])
         } else if (!(propertyname in result)) {
           result[propertyname] = otherproperties[propertyname]
         }
       }
     }
     //////////////////////////////////////
     // # class Connector
     // A connector allows to attach two objects at predefined positions
     // For example a servo motor and a servo horn:
     // Both can have a Connector called 'shaft'
     // The horn can be moved and rotated such that the two connectors match
     // and the horn is attached to the servo motor at the proper position.
     // Connectors are stored in the properties of a CSG solid so they are
     // ge the same transformations applied as the solid
   CSG.Connector = function (point, axisvector, normalvector) {
     this.point = new CSG.Vector3D(point)
     this.axisvector = new CSG.Vector3D(axisvector).unit()
     this.normalvector = new CSG.Vector3D(normalvector).unit()
   }
   CSG.Connector.prototype = {
     normalized: function () {
       var axisvector = this.axisvector.unit()
         // make the normal vector truly normal:
       var n = this.normalvector.cross(axisvector).unit()
       var normalvector = axisvector.cross(n)
       return new CSG.Connector(this.point, axisvector, normalvector)
     },
     transform: function (matrix4x4) {
       var point = this.point.multiply4x4(matrix4x4)
       var axisvector = this.point.plus(this.axisvector).multiply4x4(matrix4x4).minus(point)
       var normalvector = this.point.plus(this.normalvector).multiply4x4(matrix4x4).minus(point)
       return new CSG.Connector(point, axisvector, normalvector)
     },
     // Get the transformation matrix to connect this Connector to another connector
     //   other: a CSG.Connector to which this connector should be connected
     //   mirror: false: the 'axis' vectors of the connectors should point in the same direction
     //           true: the 'axis' vectors of the connectors should point in opposite direction
     //   normalrotation: degrees of rotation between the 'normal' vectors of the two
     //                   connectors
     getTransformationTo: function (other, mirror, normalrotation) {
       mirror = mirror ? true : false
       normalrotation = normalrotation ? Number(normalrotation) : 0
       var us = this.normalized()
       other = other.normalized()
         // shift to the origin:
       var transformation = CSG.Matrix4x4.translation(this.point.negated())
         // construct the plane crossing through the origin and the two axes:
       var axesplane = CSG.Plane.anyPlaneFromVector3Ds(
         new CSG.Vector3D(0, 0, 0), us.axisvector, other.axisvector)
       var axesbasis = new CSG.OrthoNormalBasis(axesplane)
       var angle1 = axesbasis.to2D(us.axisvector).angle()
       var angle2 = axesbasis.to2D(other.axisvector).angle()
       var rotation = 180.0 * (angle2 - angle1) / Math.PI
       if (mirror) rotation += 180.0
       transformation = transformation.multiply(axesbasis.getProjectionMatrix())
       transformation = transformation.multiply(CSG.Matrix4x4.rotationZ(rotation))
       transformation = transformation.multiply(axesbasis.getInverseProjectionMatrix())
       var usAxesAligned = us.transform(transformation)
         // Now we have done the transformation for aligning the axes.
         // We still need to align the normals:
       var normalsplane = CSG.Plane.fromNormalAndPoint(other.axisvector, new CSG.Vector3D(0, 0, 0))
       var normalsbasis = new CSG.OrthoNormalBasis(normalsplane)
       angle1 = normalsbasis.to2D(usAxesAligned.normalvector).angle()
       angle2 = normalsbasis.to2D(other.normalvector).angle()
       rotation = 180.0 * (angle2 - angle1) / Math.PI
       rotation += normalrotation
       transformation = transformation.multiply(normalsbasis.getProjectionMatrix())
       transformation = transformation.multiply(CSG.Matrix4x4.rotationZ(rotation))
       transformation = transformation.multiply(normalsbasis.getInverseProjectionMatrix())
         // and translate to the destination point:
       transformation = transformation.multiply(CSG.Matrix4x4.translation(other.point))
         // var usAligned = us.transform(transformation);
       return transformation
     },
     axisLine: function () {
       return new CSG.Line3D(this.point, this.axisvector)
     },
     // creates a new Connector, with the connection point moved in the direction of the axisvector
     extend: function (distance) {
       var newpoint = this.point.plus(this.axisvector.unit().times(distance))
       return new CSG.Connector(newpoint, this.axisvector, this.normalvector)
     }
   }
   CSG.ConnectorList = function (connectors) {
     this.connectors_ = connectors ? connectors.slice() : []
   }
   CSG.ConnectorList.defaultNormal = [0, 0, 1]
   CSG.ConnectorList.fromPath2D = function (path2D, arg1, arg2) {
       if (arguments.length === 3) {
         return CSG.ConnectorList._fromPath2DTangents(path2D, arg1, arg2)
       } else if (arguments.length === 2) {
         return CSG.ConnectorList._fromPath2DExplicit(path2D, arg1)
       } else {
         throw ("call with path2D and either 2 direction vectors, or a function returning direction vectors")
       }
     }
     /*
      * calculate the connector axisvectors by calculating the "tangent" for path2D.
      * This is undefined for start and end points, so axis for these have to be manually
      * provided.
      */
   CSG.ConnectorList._fromPath2DTangents = function (path2D, start, end) {
       // path2D
       var axis
       var pathLen = path2D.points.length
       var result = new CSG.ConnectorList([new CSG.Connector(path2D.points[0],
           start, CSG.ConnectorList.defaultNormal)])
         // middle points
       path2D.points.slice(1, pathLen - 1).forEach(function (p2, i) {
         axis = path2D.points[i + 2].minus(path2D.points[i]).toVector3D(0)
         result.appendConnector(new CSG.Connector(p2.toVector3D(0), axis,
           CSG.ConnectorList.defaultNormal))
       }, this)
       result.appendConnector(new CSG.Connector(path2D.points[pathLen - 1], end,
         CSG.ConnectorList.defaultNormal))
       result.closed = path2D.closed
       return result
     }
     /*
      * angleIsh: either a static angle, or a function(point) returning an angle
      */
   CSG.ConnectorList._fromPath2DExplicit = function (path2D, angleIsh) {
     function getAngle(angleIsh, pt, i) {
       if (typeof angleIsh === 'function') {
         angleIsh = angleIsh(pt, i)
       }
       return angleIsh
     }
     var result = new CSG.ConnectorList(
       path2D.points.map(function (p2, i) {
         return new CSG.Connector(p2.toVector3D(0),
           CSG.Vector3D.Create(1, 0, 0).rotateZ(getAngle(angleIsh, p2, i)),
           CSG.ConnectorList.defaultNormal)
       }, this)
     )
     result.closed = path2D.closed
     return result
   }
   CSG.ConnectorList.prototype = {
       setClosed: function (bool) {
         this.closed = !!closed
       },
       appendConnector: function (conn) {
         this.connectors_.push(conn)
       },
       /*
        * arguments: cagish: a cag or a function(connector) returning a cag
        *            closed: whether the 3d path defined by connectors location
        *              should be closed or stay open
        *              Note: don't duplicate connectors in the path
        * TODO: consider an option "maySelfIntersect" to close & force union all single segments
        */
       followWith: function (cagish) {
         this.verify()

         function getCag(cagish, connector) {
           if (typeof cagish === "function") {
             cagish = cagish(connector.point, connector.axisvector, connector.normalvector)
           }
           return cagish
         }
         var polygons = [],
           currCag
         var prevConnector = this.connectors_[this.connectors_.length - 1]
         var prevCag = getCag(cagish, prevConnector)
           // add walls
         this.connectors_.forEach(function (connector, notFirst) {
           currCag = getCag(cagish, connector)
           if (notFirst || this.closed) {
             polygons.push.apply(polygons, prevCag._toWallPolygons({
               toConnector1: prevConnector,
               toConnector2: connector,
               cag: currCag
             }))
           } else {
             // it is the first, and shape not closed -> build start wall
             polygons.push.apply(polygons,
               currCag._toPlanePolygons({
                 toConnector: connector,
                 flipped: true
               }))
           }
           if (notFirst === this.connectors_.length - 1 && !this.closed) {
             // build end wall
             polygons.push.apply(polygons,
               currCag._toPlanePolygons({
                 toConnector: connector
               }))
           }
           prevCag = currCag
           prevConnector = connector
         }, this)
         return CSG.fromPolygons(polygons).reTesselated().canonicalized()
       },
       /*
        * general idea behind these checks: connectors need to have smooth transition from one to another
        * TODO: add a check that 2 follow-on CAGs are not intersecting
        */
       verify: function () {
         var connI, connI1, dPosToAxis, axisToNextAxis
         for (var i = 0; i < this.connectors_.length - 1; i++) {
           connI = this.connectors_[i], connI1 = this.connectors_[i + 1]
           if (connI1.point.minus(connI.point).dot(connI.axisvector) <= 0) {
             throw ("Invalid ConnectorList. Each connectors position needs to be within a <90deg range of previous connectors axisvector")
           }
           if (connI.axisvector.dot(connI1.axisvector) <= 0) {
             throw ("invalid ConnectorList. No neighboring connectors axisvectors may span a >=90deg angle")
           }
         }
       }
     }
     //////////////////////////////////////
     // # Class Path2D
   CSG.Path2D = function (points, closed) {
       closed = !!closed
       points = points || []
         // re-parse the points into CSG.Vector2D
         // and remove any duplicate points
       var prevpoint = null
       if (closed && (points.length > 0)) {
         prevpoint = new CSG.Vector2D(points[points.length - 1])
       }
       var newpoints = []
       points.map(function (point) {
         point = new CSG.Vector2D(point)
         var skip = false
         if (prevpoint !== null) {
           var distance = point.distanceTo(prevpoint)
           skip = distance < 1e-5
         }
         if (!skip) newpoints.push(point)
         prevpoint = point
       })
       this.points = newpoints
       this.closed = closed
     }
     /*
     Construct a (part of a) circle. Parameters:
       options.center: the center point of the arc (CSG.Vector2D or array [x,y])
       options.radius: the circle radius (float)
       options.startangle: the starting angle of the arc, in degrees
         0 degrees corresponds to [1,0]
         90 degrees to [0,1]
         and so on
       options.endangle: the ending angle of the arc, in degrees
       options.resolution: number of points per 360 degree of rotation
       options.maketangent: adds two extra tiny line segments at both ends of the circle
         this ensures that the gradients at the edges are tangent to the circle
     Returns a CSG.Path2D. The path is not closed (even if it is a 360 degree arc).
     close() the resulting path if you want to create a true circle.
     */
   CSG.Path2D.arc = function (options) {
     var center = CSG.parseOptionAs2DVector(options, "center", 0)
     var radius = CSG.parseOptionAsFloat(options, "radius", 1)
     var startangle = CSG.parseOptionAsFloat(options, "startangle", 0)
     var endangle = CSG.parseOptionAsFloat(options, "endangle", 360)
     var resolution = CSG.parseOptionAsInt(options, "resolution", CSG.defaultResolution2D)
     var maketangent = CSG.parseOptionAsBool(options, "maketangent", false)
       // no need to make multiple turns:
     while (endangle - startangle >= 720) {
       endangle -= 360
     }
     while (endangle - startangle <= -720) {
       endangle += 360
     }
     var points = [],
       point
     var absangledif = Math.abs(endangle - startangle)
     if (absangledif < 1e-5) {
       point = CSG.Vector2D.fromAngle(startangle / 180.0 * Math.PI).times(radius)
       points.push(point.plus(center))
     } else {
       var numsteps = Math.floor(resolution * absangledif / 360) + 1
       var edgestepsize = numsteps * 0.5 / absangledif // step size for half a degree
       if (edgestepsize > 0.25) edgestepsize = 0.25
       var numsteps_mod = maketangent ? (numsteps + 2) : numsteps
       for (var i = 0; i <= numsteps_mod; i++) {
         var step = i
         if (maketangent) {
           step = (i - 1) * (numsteps - 2 * edgestepsize) / numsteps + edgestepsize
           if (step < 0) step = 0
           if (step > numsteps) step = numsteps
         }
         var angle = startangle + step * (endangle - startangle) / numsteps
         point = CSG.Vector2D.fromAngle(angle / 180.0 * Math.PI).times(radius)
         points.push(point.plus(center))
       }
     }
     return new CSG.Path2D(points, false)
   }
   CSG.Path2D.prototype = {
       concat: function (otherpath) {
         if (this.closed || otherpath.closed) {
           throw new Error("Paths must not be closed")
         }
         var newpoints = this.points.concat(otherpath.points)
         return new CSG.Path2D(newpoints)
       },
       appendPoint: function (point) {
         if (this.closed) {
           throw new Error("Path must not be closed")
         }
         point = new CSG.Vector2D(point) // cast to Vector2D
         var newpoints = this.points.concat([point])
         return new CSG.Path2D(newpoints)
       },
       appendPoints: function (points) {
         if (this.closed) {
           throw new Error("Path must not be closed")
         }
         var newpoints = this.points
         points.forEach(function (point) {
           newpoints.push(new CSG.Vector2D(point)) // cast to Vector2D
         })
         return new CSG.Path2D(newpoints)
       },
       close: function () {
         return new CSG.Path2D(this.points, true)
       },
       // Extrude the path by following it with a rectangle (upright, perpendicular to the path direction)
       // Returns a CSG solid
       //   width: width of the extrusion, in the z=0 plane
       //   height: height of the extrusion in the z direction
       //   resolution: number of segments per 360 degrees for the curve in a corner
       rectangularExtrude: function (width, height, resolution) {
         var cag = this.expandToCAG(width / 2, resolution)
         var result = cag.extrude({
           offset: [0, 0, height]
         })
         return result
       },
       // Expand the path to a CAG
       // This traces the path with a circle with radius pathradius
       expandToCAG: function (pathradius, resolution) {
         var sides = []
         var numpoints = this.points.length
         var startindex = 0
         if (this.closed && (numpoints > 2)) startindex = -1
         var prevvertex
         for (var i = startindex; i < numpoints; i++) {
           var pointindex = i
           if (pointindex < 0) pointindex = numpoints - 1
           var point = this.points[pointindex]
           var vertex = new CAG.Vertex(point)
           if (i > startindex) {
             var side = new CAG.Side(prevvertex, vertex)
             sides.push(side)
           }
           prevvertex = vertex
         }
         var shellcag = CAG.fromSides(sides)
         var expanded = shellcag.expandedShell(pathradius, resolution)
         return expanded
       },
       innerToCAG: function () {
         if (!this.closed) throw new Error("The path should be closed!")
         return CAG.fromPoints(this.points)
       },
       transform: function (matrix4x4) {
         var newpoints = this.points.map(function (point) {
           return point.multiply4x4(matrix4x4)
         })
         return new CSG.Path2D(newpoints, this.closed)
       },
       appendBezier: function (controlpoints, options) {
         if (arguments.length < 2) {
           options = {}
         }
         if (this.closed) {
           throw new Error("Path must not be closed")
         }
         if (!(controlpoints instanceof Array)) {
           throw new Error("appendBezier: should pass an array of control points")
         }
         if (controlpoints.length < 1) {
           throw new Error("appendBezier: need at least 1 control point")
         }
         if (this.points.length < 1) {
           throw new Error("appendBezier: path must already contain a point (the endpoint of the path is used as the starting point for the bezier curve)")
         }
         var resolution = CSG.parseOptionAsInt(options, "resolution", CSG.defaultResolution2D)
         if (resolution < 4) resolution = 4
         var factorials = []
         var controlpoints_parsed = []
         controlpoints_parsed.push(this.points[this.points.length - 1]) // start at the previous end point
         for (var i = 0; i < controlpoints.length; ++i) {
           var p = controlpoints[i]
           if (p === null) {
             // we can pass null as the first control point. In that case a smooth gradient is ensured:
             if (i !== 0) {
               throw new Error("appendBezier: null can only be passed as the first control point")
             }
             if (controlpoints.length < 2) {
               throw new Error("appendBezier: null can only be passed if there is at least one more control point")
             }
             var lastBezierControlPoint
             if ('lastBezierControlPoint' in this) {
               lastBezierControlPoint = this.lastBezierControlPoint
             } else {
               if (this.points.length < 2) {
                 throw new Error("appendBezier: null is passed as a control point but this requires a previous bezier curve or at least two points in the existing path")
               }
               lastBezierControlPoint = this.points[this.points.length - 2]
             }
             // mirror the last bezier control point:
             p = this.points[this.points.length - 1].times(2).minus(lastBezierControlPoint)
           } else {
             p = new CSG.Vector2D(p) // cast to Vector2D
           }
           controlpoints_parsed.push(p)
         }
         var bezier_order = controlpoints_parsed.length - 1
         var fact = 1
         for (var i = 0; i <= bezier_order; ++i) {
           if (i > 0) fact *= i
           factorials.push(fact)
         }
         var binomials = []
         for (var i = 0; i <= bezier_order; ++i) {
           var binomial = factorials[bezier_order] / (factorials[i] * factorials[bezier_order - i])
           binomials.push(binomial)
         }
         var getPointForT = function (t) {
           var t_k = 1 // = pow(t,k)
           var one_minus_t_n_minus_k = Math.pow(1 - t, bezier_order) // = pow( 1-t, bezier_order - k)
           var inv_1_minus_t = (t !== 1) ? (1 / (1 - t)) : 1
           var point = new CSG.Vector2D(0, 0)
           for (var k = 0; k <= bezier_order; ++k) {
             if (k === bezier_order) one_minus_t_n_minus_k = 1
             var bernstein_coefficient = binomials[k] * t_k * one_minus_t_n_minus_k
             point = point.plus(controlpoints_parsed[k].times(bernstein_coefficient))
             t_k *= t
             one_minus_t_n_minus_k *= inv_1_minus_t
           }
           return point
         }
         var newpoints = []
         var newpoints_t = []
         var numsteps = bezier_order + 1
         for (var i = 0; i < numsteps; ++i) {
           var t = i / (numsteps - 1)
           var point = getPointForT(t)
           newpoints.push(point)
           newpoints_t.push(t)
         }
         // subdivide each segment until the angle at each vertex becomes small enough:
         var subdivide_base = 1
         var maxangle = Math.PI * 2 / resolution // segments may have differ no more in angle than this
         var maxsinangle = Math.sin(maxangle)
         while (subdivide_base < newpoints.length - 1) {
           var dir1 = newpoints[subdivide_base].minus(newpoints[subdivide_base - 1]).unit()
           var dir2 = newpoints[subdivide_base + 1].minus(newpoints[subdivide_base]).unit()
           var sinangle = dir1.cross(dir2) // this is the sine of the angle
           if (Math.abs(sinangle) > maxsinangle) {
             // angle is too big, we need to subdivide
             var t0 = newpoints_t[subdivide_base - 1]
             var t1 = newpoints_t[subdivide_base + 1]
             var t0_new = t0 + (t1 - t0) * 1 / 3
             var t1_new = t0 + (t1 - t0) * 2 / 3
             var point0_new = getPointForT(t0_new)
             var point1_new = getPointForT(t1_new)
               // remove the point at subdivide_base and replace with 2 new points:
             newpoints.splice(subdivide_base, 1, point0_new, point1_new)
             newpoints_t.splice(subdivide_base, 1, t0_new, t1_new)
               // re - evaluate the angles, starting at the previous junction since it has changed:
             subdivide_base--
             if (subdivide_base < 1) subdivide_base = 1
           } else {
             ++subdivide_base
           }
         }
         // append to the previous points, but skip the first new point because it is identical to the last point:
         newpoints = this.points.concat(newpoints.slice(1))
         var result = new CSG.Path2D(newpoints)
         result.lastBezierControlPoint = controlpoints_parsed[controlpoints_parsed.length - 2]
         return result
       },
       /*
        options:
        .resolution // smoothness of the arc (number of segments per 360 degree of rotation)
        // to create a circular arc:
        .radius
        // to create an elliptical arc:
        .xradius
        .yradius
        .xaxisrotation  // the rotation (in degrees) of the x axis of the ellipse with respect to the x axis of our coordinate system
        // this still leaves 4 possible arcs between the two given points. The following two flags select which one we draw:
        .clockwise // = true | false (default is false). Two of the 4 solutions draw clockwise with respect to the center point, the other 2 counterclockwise
        .large     // = true | false (default is false). Two of the 4 solutions are an arc longer than 180 degrees, the other two are <= 180 degrees
        This implementation follows the SVG arc specs. For the details see
        http://www.w3.org/TR/SVG/paths.html#PathDataEllipticalArcCommands
        */
       appendArc: function (endpoint, options) {
         var decimals = 100000
         if (arguments.length < 2) {
           options = {}
         }
         if (this.closed) {
           throw new Error("Path must not be closed")
         }
         if (this.points.length < 1) {
           throw new Error("appendArc: path must already contain a point (the endpoint of the path is used as the starting point for the arc)")
         }
         var resolution = CSG.parseOptionAsInt(options, "resolution", CSG.defaultResolution2D)
         if (resolution < 4) resolution = 4
         var xradius, yradius
         if (('xradius' in options) || ('yradius' in options)) {
           if ('radius' in options) {
             throw new Error("Should either give an xradius and yradius parameter, or a radius parameter")
           }
           xradius = CSG.parseOptionAsFloat(options, "xradius", 0)
           yradius = CSG.parseOptionAsFloat(options, "yradius", 0)
         } else {
           xradius = CSG.parseOptionAsFloat(options, "radius", 0)
           yradius = xradius
         }
         var xaxisrotation = CSG.parseOptionAsFloat(options, "xaxisrotation", 0)
         var clockwise = CSG.parseOptionAsBool(options, "clockwise", false)
         var largearc = CSG.parseOptionAsBool(options, "large", false)
         var startpoint = this.points[this.points.length - 1]
         endpoint = new CSG.Vector2D(endpoint)
           // round to precision in order to have determinate calculations
         xradius = Math.round(xradius * decimals) / decimals
         yradius = Math.round(yradius * decimals) / decimals
         endpoint = new CSG.Vector2D(Math.round(endpoint.x * decimals) / decimals, Math.round(endpoint.y * decimals) / decimals)
         var sweep_flag = !clockwise
         var newpoints = []
         if ((xradius === 0) || (yradius === 0)) {
           // http://www.w3.org/TR/SVG/implnote.html#ArcImplementationNotes:
           // If rx = 0 or ry = 0, then treat this as a straight line from (x1, y1) to (x2, y2) and stop
           newpoints.push(endpoint)
         } else {
           xradius = Math.abs(xradius)
           yradius = Math.abs(yradius)
             // see http://www.w3.org/TR/SVG/implnote.html#ArcImplementationNotes :
           var phi = xaxisrotation * Math.PI / 180.0
           var cosphi = Math.cos(phi)
           var sinphi = Math.sin(phi)
           var minushalfdistance = startpoint.minus(endpoint).times(0.5)
             // F.6.5.1:
             // round to precision in order to have determinate calculations
           var x = Math.round((cosphi * minushalfdistance.x + sinphi * minushalfdistance.y) * decimals) / decimals
           var y = Math.round((-sinphi * minushalfdistance.x + cosphi * minushalfdistance.y) * decimals) / decimals
           var start_translated = new CSG.Vector2D(x, y)
             // F.6.6.2:
           var biglambda = start_translated.x * start_translated.x / (xradius * xradius) + start_translated.y * start_translated.y / (yradius * yradius)
           if (biglambda > 1) {
             // F.6.6.3:
             var sqrtbiglambda = Math.sqrt(biglambda)
             xradius *= sqrtbiglambda
             yradius *= sqrtbiglambda
               // round to precision in order to have determinate calculations
             xradius = Math.round(xradius * decimals) / decimals
             yradius = Math.round(yradius * decimals) / decimals
           }
           // F.6.5.2:
           var multiplier1 = Math.sqrt((xradius * xradius * yradius * yradius - xradius * xradius * start_translated.y * start_translated.y - yradius * yradius * start_translated.x * start_translated.x) / (xradius * xradius * start_translated.y * start_translated.y + yradius * yradius * start_translated.x * start_translated.x))
           if (sweep_flag === largearc) multiplier1 = -multiplier1
           var center_translated = new CSG.Vector2D(xradius * start_translated.y / yradius, -yradius * start_translated.x / xradius).times(multiplier1)
             // F.6.5.3:
           var center = new CSG.Vector2D(cosphi * center_translated.x - sinphi * center_translated.y, sinphi * center_translated.x + cosphi * center_translated.y).plus((startpoint.plus(endpoint)).times(0.5))
             // F.6.5.5:
           var vec1 = new CSG.Vector2D((start_translated.x - center_translated.x) / xradius, (start_translated.y - center_translated.y) / yradius)
           var vec2 = new CSG.Vector2D((-start_translated.x - center_translated.x) / xradius, (-start_translated.y - center_translated.y) / yradius)
           var theta1 = vec1.angleRadians()
           var theta2 = vec2.angleRadians()
           var deltatheta = theta2 - theta1
           deltatheta = deltatheta % (2 * Math.PI)
           if ((!sweep_flag) && (deltatheta > 0)) {
             deltatheta -= 2 * Math.PI
           } else if ((sweep_flag) && (deltatheta < 0)) {
             deltatheta += 2 * Math.PI
           }
           // Ok, we have the center point and angle range (from theta1, deltatheta radians) so we can create the ellipse
           var numsteps = Math.ceil(Math.abs(deltatheta) / (2 * Math.PI) * resolution) + 1
           if (numsteps < 1) numsteps = 1
           for (var step = 1; step <= numsteps; step++) {
             var theta = theta1 + step / numsteps * deltatheta
             var costheta = Math.cos(theta)
             var sintheta = Math.sin(theta)
               // F.6.3.1:
             var point = new CSG.Vector2D(cosphi * xradius * costheta - sinphi * yradius * sintheta, sinphi * xradius * costheta + cosphi * yradius * sintheta).plus(center)
             newpoints.push(point)
           }
         }
         newpoints = this.points.concat(newpoints)
         var result = new CSG.Path2D(newpoints)
         return result
       },
     }
     // Add several convenience methods to the classes that support a transform() method:
   CSG.addTransformationMethodsToPrototype = function (prot) {
       prot.mirrored = function (plane) {
         return this.transform(CSG.Matrix4x4.mirroring(plane))
       }
       prot.mirroredX = function () {
         var plane = new CSG.Plane(CSG.Vector3D.Create(1, 0, 0), 0)
         return this.mirrored(plane)
       }
       prot.mirroredY = function () {
         var plane = new CSG.Plane(CSG.Vector3D.Create(0, 1, 0), 0)
         return this.mirrored(plane)
       }
       prot.mirroredZ = function () {
         var plane = new CSG.Plane(CSG.Vector3D.Create(0, 0, 1), 0)
         return this.mirrored(plane)
       }
       prot.translate = function (v) {
         return this.transform(CSG.Matrix4x4.translation(v))
       }
       prot.scale = function (f) {
         return this.transform(CSG.Matrix4x4.scaling(f))
       }
       prot.rotateX = function (deg) {
         return this.transform(CSG.Matrix4x4.rotationX(deg))
       }
       prot.rotateY = function (deg) {
         return this.transform(CSG.Matrix4x4.rotationY(deg))
       }
       prot.rotateZ = function (deg) {
         return this.transform(CSG.Matrix4x4.rotationZ(deg))
       }
       prot.rotate = function (rotationCenter, rotationAxis, degrees) {
         return this.transform(CSG.Matrix4x4.rotation(rotationCenter, rotationAxis, degrees))
       }
       prot.rotateEulerAngles = function (alpha, beta, gamma, position) {
         position = position || [0, 0, 0]
         var Rz1 = CSG.Matrix4x4.rotationZ(alpha)
         var Rx = CSG.Matrix4x4.rotationX(beta)
         var Rz2 = CSG.Matrix4x4.rotationZ(gamma)
         var T = CSG.Matrix4x4.translation(new CSG.Vector3D(position))
         return this.transform(Rz2.multiply(Rx).multiply(Rz1).multiply(T))
       }
     }
     // TODO: consider generalization and adding to addTransformationMethodsToPrototype
   CSG.addCenteringToPrototype = function (prot, axes) {
       prot.center = function (cAxes) {
         cAxes = Array.prototype.map.call(arguments, function (a) {
             return a.toLowerCase()
           })
           // no args: center on all axes
         if (!cAxes.length) {
           cAxes = axes.slice()
         }
         var b = this.getBounds()
         return this.translate(axes.map(function (a) {
           return cAxes.indexOf(a) > -1 ?
             -(b[0][a] + b[1][a]) / 2 : 0
         }))
       }
     }
     //////////////////
     // CAG: solid area geometry: like CSG but 2D
     // Each area consists of a number of sides
     // Each side is a line between 2 points
   var CAG = function () {
       this.sides = []
     }
     // Construct a CAG from a list of `CAG.Side` instances.
   CAG.fromSides = function (sides) {
       var cag = new CAG()
       cag.sides = sides
       return cag
     }
     // Construct a CAG from a list of points (a polygon)
     // Rotation direction of the points is not relevant. Points can be a convex or concave polygon.
     // Polygon must not self intersect
   CAG.fromPoints = function (points) {
       var numpoints = points.length
       if (numpoints < 3) throw new Error("CAG shape needs at least 3 points")
       var sides = []
       var prevpoint = new CSG.Vector2D(points[numpoints - 1])
       var prevvertex = new CAG.Vertex(prevpoint)
       points.map(function (p) {
         var point = new CSG.Vector2D(p)
         var vertex = new CAG.Vertex(point)
         var side = new CAG.Side(prevvertex, vertex)
         sides.push(side)
         prevvertex = vertex
       })
       var result = CAG.fromSides(sides)
       if (result.isSelfIntersecting()) {
         throw new Error("Polygon is self intersecting!")
       }
       var area = result.area()
       if (Math.abs(area) < 1e-5) {
         throw new Error("Degenerate polygon!")
       }
       if (area < 0) {
         result = result.flipped()
       }
       result = result.canonicalized()
       return result
     }
     // Like CAG.fromPoints but does not check if it's a valid polygon.
     // Points should rotate counter clockwise
   CAG.fromPointsNoCheck = function (points) {
       var sides = []
       var prevpoint = new CSG.Vector2D(points[points.length - 1])
       var prevvertex = new CAG.Vertex(prevpoint)
       points.map(function (p) {
         var point = new CSG.Vector2D(p)
         var vertex = new CAG.Vertex(point)
         var side = new CAG.Side(prevvertex, vertex)
         sides.push(side)
         prevvertex = vertex
       })
       return CAG.fromSides(sides)
     }
     // Converts a CSG to a CAG. The CSG must consist of polygons with only z coordinates +1 and -1
     // as constructed by CAG._toCSGWall(-1, 1). This is so we can use the 3D union(), intersect() etc
   CAG.fromFakeCSG = function (csg) {
       var sides = csg.polygons.map(function (p) {
           return CAG.Side._fromFakePolygon(p)
         })
         .filter(function (s) {
           return s !== null
         })
       return CAG.fromSides(sides)
     }
     // see if the line between p0start and p0end intersects with the line between p1start and p1end
     // returns true if the lines strictly intersect, the end points are not counted!
   CAG.linesIntersect = function (p0start, p0end, p1start, p1end) {
       if (p0end.equals(p1start) || p1end.equals(p0start)) {
         var d = p1end.minus(p1start).unit().plus(p0end.minus(p0start).unit()).length()
         if (d < 1e-5) {
           return true
         }
       } else {
         var d0 = p0end.minus(p0start)
         var d1 = p1end.minus(p1start)
         if (Math.abs(d0.cross(d1)) < 1e-9) return false // lines are parallel
         var alphas = CSG.solve2Linear(-d0.x, d1.x, -d0.y, d1.y, p0start.x - p1start.x, p0start.y - p1start.y)
         if ((alphas[0] > 1e-6) && (alphas[0] < 0.999999) && (alphas[1] > 1e-5) && (alphas[1] < 0.999999)) return true
           //    if( (alphas[0] >= 0) && (alphas[0] <= 1) && (alphas[1] >= 0) && (alphas[1] <= 1) ) return true;
       }
       return false
     }
     /* Construct a circle
     options:
       center: a 2D center point
       radius: a scalar
       resolution: number of sides per 360 degree rotation
     returns a CAG object
     */
   CAG.circle = function (options) {
       options = options || {}
       var center = CSG.parseOptionAs2DVector(options, "center", [0, 0])
       var radius = CSG.parseOptionAsFloat(options, "radius", 1)
       var resolution = CSG.parseOptionAsInt(options, "resolution", CSG.defaultResolution2D)
       var sides = []
       var prevvertex
       for (var i = 0; i <= resolution; i++) {
         var radians = 2 * Math.PI * i / resolution
         var point = CSG.Vector2D.fromAngleRadians(radians).times(radius).plus(center)
         var vertex = new CAG.Vertex(point)
         if (i > 0) {
           sides.push(new CAG.Side(prevvertex, vertex))
         }
         prevvertex = vertex
       }
       return CAG.fromSides(sides)
     }
     /* Construct a rectangle
     options:
       center: a 2D center point
       radius: a 2D vector with width and height
       returns a CAG object
     */
   CAG.rectangle = function (options) {
       options = options || {}
       var c, r
       if (('corner1' in options) || ('corner2' in options)) {
         if (('center' in options) || ('radius' in options)) {
           throw new Error("rectangle: should either give a radius and center parameter, or a corner1 and corner2 parameter")
         }
         corner1 = CSG.parseOptionAs2DVector(options, "corner1", [0, 0])
         corner2 = CSG.parseOptionAs2DVector(options, "corner2", [1, 1])
         c = corner1.plus(corner2).times(0.5)
         r = corner2.minus(corner1).times(0.5)
       } else {
         c = CSG.parseOptionAs2DVector(options, "center", [0, 0])
         r = CSG.parseOptionAs2DVector(options, "radius", [1, 1])
       }
       r = r.abs() // negative radii make no sense
       var rswap = new CSG.Vector2D(r.x, -r.y)
       var points = [
         c.plus(r), c.plus(rswap), c.minus(r), c.minus(rswap)
       ]
       return CAG.fromPoints(points)
     }
     //     var r = CSG.roundedRectangle({
     //       center: [0, 0],
     //       radius: [2, 1],
     //       roundradius: 0.2,
     //       resolution: 8,
     //     });
   CAG.roundedRectangle = function (options) {
       options = options || {}
       var center, radius
       if (('corner1' in options) || ('corner2' in options)) {
         if (('center' in options) || ('radius' in options)) {
           throw new Error("roundedRectangle: should either give a radius and center parameter, or a corner1 and corner2 parameter")
         }
         corner1 = CSG.parseOptionAs2DVector(options, "corner1", [0, 0])
         corner2 = CSG.parseOptionAs2DVector(options, "corner2", [1, 1])
         center = corner1.plus(corner2).times(0.5)
         radius = corner2.minus(corner1).times(0.5)
       } else {
         center = CSG.parseOptionAs2DVector(options, "center", [0, 0])
         radius = CSG.parseOptionAs2DVector(options, "radius", [1, 1])
       }
       radius = radius.abs() // negative radii make no sense
       var roundradius = CSG.parseOptionAsFloat(options, "roundradius", 0.2)
       var resolution = CSG.parseOptionAsInt(options, "resolution", CSG.defaultResolution2D)
       var maxroundradius = Math.min(radius.x, radius.y)
       maxroundradius -= 0.1
       roundradius = Math.min(roundradius, maxroundradius)
       roundradius = Math.max(0, roundradius)
       radius = new CSG.Vector2D(radius.x - roundradius, radius.y - roundradius)
       var rect = CAG.rectangle({
         center: center,
         radius: radius
       })
       if (roundradius > 0) {
         rect = rect.expand(roundradius, resolution)
       }
       return rect
     }
     // Reconstruct a CAG from the output of toCompactBinary()
   CAG.fromCompactBinary = function (bin) {
     if (bin['class'] !== "CAG") throw new Error("Not a CAG")
     var vertices = []
     var vertexData = bin.vertexData
     var numvertices = vertexData.length / 2
     var arrayindex = 0
     for (var vertexindex = 0; vertexindex < numvertices; vertexindex++) {
       var x = vertexData[arrayindex++]
       var y = vertexData[arrayindex++]
       var pos = new CSG.Vector2D(x, y)
       var vertex = new CAG.Vertex(pos)
       vertices.push(vertex)
     }
     var sides = []
     var numsides = bin.sideVertexIndices.length / 2
     arrayindex = 0
     for (var sideindex = 0; sideindex < numsides; sideindex++) {
       var vertexindex0 = bin.sideVertexIndices[arrayindex++]
       var vertexindex1 = bin.sideVertexIndices[arrayindex++]
       var side = new CAG.Side(vertices[vertexindex0], vertices[vertexindex1])
       sides.push(side)
     }
     var cag = CAG.fromSides(sides)
     cag.isCanonicalized = true
     return cag
   }

   function fnSortByIndex(a, b) {
     return a.index - b.index
   }
   CAG.prototype = {
     toString: function () {
       var result = "CAG (" + this.sides.length + " sides):\n"
       this.sides.map(function (side) {
         result += "  " + side.toString() + "\n"
       })
       return result
     },
     _toCSGWall: function (z0, z1) {
       var polygons = this.sides.map(function (side) {
         return side.toPolygon3D(z0, z1)
       })
       return CSG.fromPolygons(polygons)
     },
     _toVector3DPairs: function (m) {
       // transform m
       var pairs = this.sides.map(function (side) {
         var p0 = side.vertex0.pos,
           p1 = side.vertex1.pos
         return [CSG.Vector3D.Create(p0.x, p0.y, 0),
           CSG.Vector3D.Create(p1.x, p1.y, 0)
         ]
       })
       if (typeof m !== 'undefined') {
         pairs = pairs.map(function (pair) {
           return pair.map(function (v) {
             return v.transform(m)
           })
         })
       }
       return pairs
     },
     /*
      * transform a cag into the polygons of a corresponding 3d plane, positioned per options
      * Accepts a connector for plane positioning, or optionally
      * single translation, axisVector, normalVector arguments
      * (toConnector has precedence over single arguments if provided)
      */
     _toPlanePolygons: function (options) {
       var flipped = options.flipped || false
         // reference connector for transformation
       var origin = [0, 0, 0],
         defaultAxis = [0, 0, 1],
         defaultNormal = [0, 1, 0]
       var thisConnector = new CSG.Connector(origin, defaultAxis, defaultNormal)
         // translated connector per options
       var translation = options.translation || origin
       var axisVector = options.axisVector || defaultAxis
       var normalVector = options.normalVector || defaultNormal
         // will override above if options has toConnector
       var toConnector = options.toConnector ||
         new CSG.Connector(translation, axisVector, normalVector)
         // resulting transform
       var m = thisConnector.getTransformationTo(toConnector, false, 0)
         // create plane as a (partial non-closed) CSG in XY plane
       var bounds = this.getBounds()
       bounds[0] = bounds[0].minus(new CSG.Vector2D(1, 1))
       bounds[1] = bounds[1].plus(new CSG.Vector2D(1, 1))
       var csgshell = this._toCSGWall(-1, 1)
       var csgplane = CSG.fromPolygons([new CSG.Polygon([
         new CSG.Vertex(new CSG.Vector3D(bounds[0].x, bounds[0].y, 0)),
         new CSG.Vertex(new CSG.Vector3D(bounds[1].x, bounds[0].y, 0)),
         new CSG.Vertex(new CSG.Vector3D(bounds[1].x, bounds[1].y, 0)),
         new CSG.Vertex(new CSG.Vector3D(bounds[0].x, bounds[1].y, 0))
       ])])
       if (flipped) {
         csgplane = csgplane.invert()
       }
       // intersectSub -> prevent premature retesselate/canonicalize
       csgplane = csgplane.intersectSub(csgshell)
         // only keep the polygons in the z plane:
       var polys = csgplane.polygons.filter(function (polygon) {
           return Math.abs(polygon.plane.normal.z) > 0.99
         })
         // finally, position the plane per passed transformations
       return polys.map(function (poly) {
         return poly.transform(m)
       })
     },
     /*
      * given 2 connectors, this returns all polygons of a "wall" between 2
      * copies of this cag, positioned in 3d space as "bottom" and
      * "top" plane per connectors toConnector1, and toConnector2, respectively
      */
     _toWallPolygons: function (options) {
       // normals are going to be correct as long as toConn2.point - toConn1.point
       // points into cag normal direction (check in caller)
       // arguments: options.toConnector1, options.toConnector2, options.cag
       //     walls go from toConnector1 to toConnector2
       //     optionally, target cag to point to - cag needs to have same number of sides as this!
       var origin = [0, 0, 0],
         defaultAxis = [0, 0, 1],
         defaultNormal = [0, 1, 0]
       var thisConnector = new CSG.Connector(origin, defaultAxis, defaultNormal)
         // arguments:
       var toConnector1 = options.toConnector1
         // var toConnector2 = new CSG.Connector([0, 0, -30], defaultAxis, defaultNormal);
       var toConnector2 = options.toConnector2
       if (!(toConnector1 instanceof CSG.Connector && toConnector2 instanceof CSG.Connector)) {
         throw ('could not parse CSG.Connector arguments toConnector1 or toConnector2')
       }
       if (options.cag) {
         if (options.cag.sides.length !== this.sides.length) {
           throw ('target cag needs same sides count as start cag')
         }
       }
       // target cag is same as this unless specified
       var toCag = options.cag || this
       var m1 = thisConnector.getTransformationTo(toConnector1, false, 0)
       var m2 = thisConnector.getTransformationTo(toConnector2, false, 0)
       var vps1 = this._toVector3DPairs(m1)
       var vps2 = toCag._toVector3DPairs(m2)
       var polygons = []
       vps1.forEach(function (vp1, i) {
         polygons.push(new CSG.Polygon([
           new CSG.Vertex(vps2[i][1]), new CSG.Vertex(vps2[i][0]), new CSG.Vertex(vp1[0])
         ]))
         polygons.push(new CSG.Polygon([
           new CSG.Vertex(vps2[i][1]), new CSG.Vertex(vp1[0]), new CSG.Vertex(vp1[1])
         ]))
       })
       return polygons
     },
     union: function (cag) {
       var cags
       if (cag instanceof Array) {
         cags = cag
       } else {
         cags = [cag]
       }
       var r = this._toCSGWall(-1, 1)
       var r = r.union(
         cags.map(function (cag) {
           return cag._toCSGWall(-1, 1).reTesselated()
         }), false, false)
       return CAG.fromFakeCSG(r).canonicalized()
     },
     subtract: function (cag) {
       var cags
       if (cag instanceof Array) {
         cags = cag
       } else {
         cags = [cag]
       }
       var r = this._toCSGWall(-1, 1)
       cags.map(function (cag) {
         r = r.subtractSub(cag._toCSGWall(-1, 1), false, false)
       })
       r = r.reTesselated()
       r = r.canonicalized()
       r = CAG.fromFakeCSG(r)
       r = r.canonicalized()
       return r
     },
     intersect: function (cag) {
       var cags
       if (cag instanceof Array) {
         cags = cag
       } else {
         cags = [cag]
       }
       var r = this._toCSGWall(-1, 1)
       cags.map(function (cag) {
         r = r.intersectSub(cag._toCSGWall(-1, 1), false, false)
       })
       r = r.reTesselated()
       r = r.canonicalized()
       r = CAG.fromFakeCSG(r)
       r = r.canonicalized()
       return r
     },
     transform: function (matrix4x4) {
       var ismirror = matrix4x4.isMirroring()
       var newsides = this.sides.map(function (side) {
         return side.transform(matrix4x4)
       })
       var result = CAG.fromSides(newsides)
       if (ismirror) {
         result = result.flipped()
       }
       return result
     },
     // see http://local.wasp.uwa.edu.au/~pbourke/geometry/polyarea/ :
     // Area of the polygon. For a counter clockwise rotating polygon the area is positive, otherwise negative
     // Note(bebbi): this looks wrong. See polygon getArea()
     area: function () {
       var polygonArea = 0
       this.sides.map(function (side) {
         polygonArea += side.vertex0.pos.cross(side.vertex1.pos)
       })
       polygonArea *= 0.5
       return polygonArea
     },
     flipped: function () {
       var newsides = this.sides.map(function (side) {
         return side.flipped()
       })
       newsides.reverse()
       return CAG.fromSides(newsides)
     },
     getBounds: function () {
       var minpoint
       if (this.sides.length === 0) {
         minpoint = new CSG.Vector2D(0, 0)
       } else {
         minpoint = this.sides[0].vertex0.pos
       }
       var maxpoint = minpoint
       this.sides.map(function (side) {
         minpoint = minpoint.min(side.vertex0.pos)
         minpoint = minpoint.min(side.vertex1.pos)
         maxpoint = maxpoint.max(side.vertex0.pos)
         maxpoint = maxpoint.max(side.vertex1.pos)
       })
       return [minpoint, maxpoint]
     },
     isSelfIntersecting: function (debug) {
       var numsides = this.sides.length
       for (var i = 0; i < numsides; i++) {
         var side0 = this.sides[i]
         for (var ii = i + 1; ii < numsides; ii++) {
           var side1 = this.sides[ii]
           if (CAG.linesIntersect(side0.vertex0.pos, side0.vertex1.pos, side1.vertex0.pos, side1.vertex1.pos)) {
             if (debug) {
               OpenJsCad.log(side0)
               OpenJsCad.log(side1)
             }
             return true
           }
         }
       }
       return false
     },
     expandedShell: function (radius, resolution) {
       resolution = resolution || 8
       if (resolution < 4) resolution = 4
       var cags = []
       var pointmap = {}
       var cag = this.canonicalized()
       cag.sides.map(function (side) {
         var d = side.vertex1.pos.minus(side.vertex0.pos)
         var dl = d.length()
         if (dl > 1e-5) {
           d = d.times(1.0 / dl)
           var normal = d.normal().times(radius)
           var shellpoints = [
               side.vertex1.pos.plus(normal),
               side.vertex1.pos.minus(normal),
               side.vertex0.pos.minus(normal),
               side.vertex0.pos.plus(normal)
             ]
             //      var newcag = CAG.fromPointsNoCheck(shellpoints);
           var newcag = CAG.fromPoints(shellpoints)
           cags.push(newcag)
           for (var step = 0; step < 2; step++) {
             var p1 = (step === 0) ? side.vertex0.pos : side.vertex1.pos
             var p2 = (step === 0) ? side.vertex1.pos : side.vertex0.pos
             var tag = p1.x + " " + p1.y
             if (!(tag in pointmap)) {
               pointmap[tag] = []
             }
             pointmap[tag].push({
               "p1": p1,
               "p2": p2
             })
           }
         }
       })
       for (var tag in pointmap) {
         var m = pointmap[tag]
         var angle1, angle2
         var pcenter = m[0].p1
         if (m.length === 2) {
           var end1 = m[0].p2
           var end2 = m[1].p2
           angle1 = end1.minus(pcenter).angleDegrees()
           angle2 = end2.minus(pcenter).angleDegrees()
           if (angle2 < angle1) angle2 += 360
           if (angle2 >= (angle1 + 360)) angle2 -= 360
           if (angle2 < angle1 + 180) {
             var t = angle2
             angle2 = angle1 + 360
             angle1 = t
           }
           angle1 += 90
           angle2 -= 90
         } else {
           angle1 = 0
           angle2 = 360
         }
         var fullcircle = (angle2 > angle1 + 359.999)
         if (fullcircle) {
           angle1 = 0
           angle2 = 360
         }
         if (angle2 > (angle1 + 1e-5)) {
           var points = []
           if (!fullcircle) {
             points.push(pcenter)
           }
           var numsteps = Math.round(resolution * (angle2 - angle1) / 360)
           if (numsteps < 1) numsteps = 1
           for (var step = 0; step <= numsteps; step++) {
             var angle = angle1 + step / numsteps * (angle2 - angle1)
             if (step === numsteps) angle = angle2 // prevent rounding errors
             var point = pcenter.plus(CSG.Vector2D.fromAngleDegrees(angle).times(radius))
             if ((!fullcircle) || (step > 0)) {
               points.push(point)
             }
           }
           var newcag = CAG.fromPointsNoCheck(points)
           cags.push(newcag)
         }
       }
       var result = new CAG()
       result = result.union(cags)
       return result
     },
     expand: function (radius, resolution) {
       var result = this.union(this.expandedShell(radius, resolution))
       return result
     },
     contract: function (radius, resolution) {
       var result = this.subtract(this.expandedShell(radius, resolution))
       return result
     },
     // extrude the CAG in a certain plane. 
     // Giving just a plane is not enough, multiple different extrusions in the same plane would be possible
     // by rotating around the plane's origin. An additional right-hand vector should be specified as well,
     // and this is exactly a CSG.OrthoNormalBasis.
     // orthonormalbasis: characterizes the plane in which to extrude
     // depth: thickness of the extruded shape. Extrusion is done from the plane towards above (unless 
     // symmetrical option is set, see below)
     //
     // options:
     //   {symmetrical: true}  // extrude symmetrically in two directions about the plane
     extrudeInOrthonormalBasis: function (orthonormalbasis, depth, options) {
       // first extrude in the regular Z plane:
       if (!(orthonormalbasis instanceof CSG.OrthoNormalBasis)) {
         throw new Error("extrudeInPlane: the first parameter should be a CSG.OrthoNormalBasis")
       }
       var extruded = this.extrude({
         offset: [0, 0, depth]
       })
       if (CSG.parseOptionAsBool(options, "symmetrical", false)) {
         extruded = extruded.translate([0, 0, -depth / 2])
       }
       var matrix = orthonormalbasis.getInverseProjectionMatrix()
       extruded = extruded.transform(matrix)
       return extruded
     },
     // Extrude in a standard cartesian plane, specified by two axis identifiers. Each identifier can be
     // one of ["X","Y","Z","-X","-Y","-Z"]
     // The 2d x axis will map to the first given 3D axis, the 2d y axis will map to the second.
     // See CSG.OrthoNormalBasis.GetCartesian for details.
     extrudeInPlane: function (axis1, axis2, depth, options) {
       return this.extrudeInOrthonormalBasis(CSG.OrthoNormalBasis.GetCartesian(axis1, axis2), depth, options)
     },
     // extruded=cag.extrude({offset: [0,0,10], twistangle: 360, twiststeps: 100});
     // linear extrusion of 2D shape, with optional twist
     // The 2d shape is placed in in z=0 plane and extruded into direction <offset> (a CSG.Vector3D)
     // The final face is rotated <twistangle> degrees. Rotation is done around the origin of the 2d shape (i.e. x=0, y=0)
     // twiststeps determines the resolution of the twist (should be >= 1)
     // returns a CSG object
     extrude: function (options) {
       if (this.sides.length === 0) {
         // empty!
         return new CSG()
       }
       var offsetVector = CSG.parseOptionAs3DVector(options, "offset", [0, 0, 1])
       var twistangle = CSG.parseOptionAsFloat(options, "twistangle", 0)
       var twiststeps = CSG.parseOptionAsInt(options, "twiststeps", CSG.defaultResolution3D)
       if (offsetVector.z === 0) {
         throw ('offset cannot be orthogonal to Z axis')
       }
       if (twistangle === 0 || twiststeps < 1) {
         twiststeps = 1
       }
       var normalVector = CSG.Vector3D.Create(0, 1, 0)
       var polygons = []
         // bottom and top
       polygons = polygons.concat(this._toPlanePolygons({
         translation: [0, 0, 0],
         normalVector: normalVector,
         flipped: !(offsetVector.z < 0)
       }))
       polygons = polygons.concat(this._toPlanePolygons({
           translation: offsetVector,
           normalVector: normalVector.rotateZ(twistangle),
           flipped: offsetVector.z < 0
         }))
         // walls
       for (var i = 0; i < twiststeps; i++) {
         var c1 = new CSG.Connector(offsetVector.times(i / twiststeps), [0, 0, offsetVector.z],
           normalVector.rotateZ(i * twistangle / twiststeps))
         var c2 = new CSG.Connector(offsetVector.times((i + 1) / twiststeps), [0, 0, offsetVector.z],
           normalVector.rotateZ((i + 1) * twistangle / twiststeps))
         polygons = polygons.concat(this._toWallPolygons({
           toConnector1: c1,
           toConnector2: c2
         }))
       }
       return CSG.fromPolygons(polygons)
     },
     /*
      * extrude CAG to 3d object by rotating the origin around the y axis
      * (and turning everything into XY plane)
      * arguments: options dict with angle and resolution, both optional
      */
     rotateExtrude: function (options) {
       var alpha = CSG.parseOptionAsFloat(options, "angle", 360)
       var resolution = CSG.parseOptionAsInt(options, "resolution", CSG.defaultResolution3D)
       var EPS = 1e-5
       alpha = alpha > 360 ? alpha % 360 : alpha
       var origin = [0, 0, 0]
       var axisV = CSG.Vector3D.Create(0, 1, 0)
       var normalV = [0, 0, 1]
       var polygons = []
         // planes only needed if alpha > 0
       var connS = new CSG.Connector(origin, axisV, normalV)
       if (alpha > 0 && alpha < 360) {
         // we need to rotate negative to satisfy wall function condition of
         // building in the direction of axis vector
         var connE = new CSG.Connector(origin, axisV.rotateZ(-alpha), normalV)
         polygons = polygons.concat(
           this._toPlanePolygons({
             toConnector: connS,
             flipped: true
           }))
         polygons = polygons.concat(
           this._toPlanePolygons({
             toConnector: connE
           }))
       }
       var connT1 = connS,
         connT2
       var step = alpha / resolution
       for (var a = step; a <= alpha + EPS; a += step) {
         connT2 = new CSG.Connector(origin, axisV.rotateZ(-a), normalV)
         polygons = polygons.concat(this._toWallPolygons({
           toConnector1: connT1,
           toConnector2: connT2
         }))
         connT1 = connT2
       }
       return CSG.fromPolygons(polygons).reTesselated()
     },
     // check if we are a valid CAG (for debugging)
     // NOTE(bebbi) uneven side count doesn't work because rounding with EPS isn't taken into account
     check: function () {
       var EPS = 1e-5
       var errors = []
       if (this.isSelfIntersecting(true)) {
         errors.push("Self intersects")
       }
       var pointcount = {}
       this.sides.map(function (side) {
         function mappoint(p) {
           var tag = p.x + " " + p.y
           if (!(tag in pointcount)) pointcount[tag] = 0
           pointcount[tag] ++
         }
         mappoint(side.vertex0.pos)
         mappoint(side.vertex1.pos)
       })
       for (var tag in pointcount) {
         var count = pointcount[tag]
         if (count & 1) {
           errors.push("Uneven number of sides (" + count + ") for point " + tag)
         }
       }
       var area = this.area()
       if (area < EPS * EPS) {
         errors.push("Area is " + area)
       }
       if (errors.length > 0) {
         var ertxt = ""
         errors.map(function (err) {
           ertxt += err + "\n"
         })
         throw new Error(ertxt)
       }
     },
     canonicalized: function () {
       if (this.isCanonicalized) {
         return this
       } else {
         var factory = new CAG.fuzzyCAGFactory()
         var result = factory.getCAG(this)
         result.isCanonicalized = true
         return result
       }
     },
     toCompactBinary: function () {
       var cag = this.canonicalized()
       var numsides = cag.sides.length
       var vertexmap = {}
       var vertices = []
       var numvertices = 0
       var sideVertexIndices = new Uint32Array(2 * numsides)
       var sidevertexindicesindex = 0
       cag.sides.map(function (side) {
         [side.vertex0, side.vertex1].map(function (v) {
           var vertextag = v.getTag()
           var vertexindex
           if (!(vertextag in vertexmap)) {
             vertexindex = numvertices++
               vertexmap[vertextag] = vertexindex
             vertices.push(v)
           } else {
             vertexindex = vertexmap[vertextag]
           }
           sideVertexIndices[sidevertexindicesindex++] = vertexindex
         })
       })
       var vertexData = new Float64Array(numvertices * 2)
       var verticesArrayIndex = 0
       vertices.map(function (v) {
         var pos = v.pos
         vertexData[verticesArrayIndex++] = pos._x
         vertexData[verticesArrayIndex++] = pos._y
       })
       var result = {
         'class': "CAG",
         sideVertexIndices: sideVertexIndices,
         vertexData: vertexData
       }
       return result
     },
     getOutlinePaths: function () {
       var cag = this.canonicalized()
       var sideTagToSideMap = {}
       var startVertexTagToSideTagMap = {}
       cag.sides.map(function (side) {
         var sidetag = side.getTag()
         sideTagToSideMap[sidetag] = side
         var startvertextag = side.vertex0.getTag()
         if (!(startvertextag in startVertexTagToSideTagMap)) {
           startVertexTagToSideTagMap[startvertextag] = []
         }
         startVertexTagToSideTagMap[startvertextag].push(sidetag)
       })
       var paths = []
       while (true) {
         var startsidetag = null
         for (var aVertexTag in startVertexTagToSideTagMap) {
           var sidesForThisVertex = startVertexTagToSideTagMap[aVertexTag]
           startsidetag = sidesForThisVertex[0]
           sidesForThisVertex.splice(0, 1)
           if (sidesForThisVertex.length === 0) {
             delete startVertexTagToSideTagMap[aVertexTag]
           }
           break
         }
         if (startsidetag === null) break // we've had all sides
         var connectedVertexPoints = []
         var sidetag = startsidetag
         var thisside = sideTagToSideMap[sidetag]
         var startvertextag = thisside.vertex0.getTag()
         while (true) {
           connectedVertexPoints.push(thisside.vertex0.pos)
           var nextvertextag = thisside.vertex1.getTag()
           if (nextvertextag === startvertextag) break // we've closed the polygon
           if (!(nextvertextag in startVertexTagToSideTagMap)) {
             throw new Error("Area is not closed!")
           }
           var nextpossiblesidetags = startVertexTagToSideTagMap[nextvertextag]
           var nextsideindex = -1
           if (nextpossiblesidetags.length === 1) {
             nextsideindex = 0
           } else {
             // more than one side starting at the same vertex. This means we have
             // two shapes touching at the same corner
             var bestangle = null
             var thisangle = thisside.direction().angleDegrees()
             for (var sideindex = 0; sideindex < nextpossiblesidetags.length; sideindex++) {
               var nextpossiblesidetag = nextpossiblesidetags[sideindex]
               var possibleside = sideTagToSideMap[nextpossiblesidetag]
               var angle = possibleside.direction().angleDegrees()
               var angledif = angle - thisangle
               if (angledif < -180) angledif += 360
               if (angledif >= 180) angledif -= 360
               if ((nextsideindex < 0) || (angledif > bestangle)) {
                 nextsideindex = sideindex
                 bestangle = angledif
               }
             }
           }
           var nextsidetag = nextpossiblesidetags[nextsideindex]
           nextpossiblesidetags.splice(nextsideindex, 1)
           if (nextpossiblesidetags.length === 0) {
             delete startVertexTagToSideTagMap[nextvertextag]
           }
           thisside = sideTagToSideMap[nextsidetag]
         } // inner loop
         var path = new CSG.Path2D(connectedVertexPoints, true)
         paths.push(path)
       } // outer loop
       return paths
     },
     /*
     cag = cag.overCutInsideCorners(cutterradius);

     Using a CNC router it's impossible to cut out a true sharp inside corner. The inside corner
     will be rounded due to the radius of the cutter. This function compensates for this by creating
     an extra cutout at each inner corner so that the actual cut out shape will be at least as large
     as needed.
     */
     overCutInsideCorners: function (cutterradius) {
       var cag = this.canonicalized()
         // for each vertex determine the 'incoming' side and 'outgoing' side:
       var pointmap = {} // tag => {pos: coord, from: [], to: []}
       cag.sides.map(function (side) {
           if (!(side.vertex0.getTag() in pointmap)) {
             pointmap[side.vertex0.getTag()] = {
               pos: side.vertex0.pos,
               from: [],
               to: []
             }
           }
           pointmap[side.vertex0.getTag()].to.push(side.vertex1.pos)
           if (!(side.vertex1.getTag() in pointmap)) {
             pointmap[side.vertex1.getTag()] = {
               pos: side.vertex1.pos,
               from: [],
               to: []
             }
           }
           pointmap[side.vertex1.getTag()].from.push(side.vertex0.pos)
         })
         // overcut all sharp corners:
       var cutouts = []
       for (var pointtag in pointmap) {
         var pointobj = pointmap[pointtag]
         if ((pointobj.from.length === 1) && (pointobj.to.length === 1)) {
           // ok, 1 incoming side and 1 outgoing side:
           var fromcoord = pointobj.from[0]
           var pointcoord = pointobj.pos
           var tocoord = pointobj.to[0]
           var v1 = pointcoord.minus(fromcoord).unit()
           var v2 = tocoord.minus(pointcoord).unit()
           var crossproduct = v1.cross(v2)
           var isInnerCorner = (crossproduct < 0.001)
           if (isInnerCorner) {
             // yes it's a sharp corner:
             var alpha = v2.angleRadians() - v1.angleRadians() + Math.PI
             if (alpha < 0) {
               alpha += 2 * Math.PI
             } else if (alpha >= 2 * Math.PI) {
               alpha -= 2 * Math.PI
             }
             var midvector = v2.minus(v1).unit()
             var circlesegmentangle = 30 / 180 * Math.PI // resolution of the circle: segments of 30 degrees
               // we need to increase the radius slightly so that our imperfect circle will contain a perfect circle of cutterradius
             var radiuscorrected = cutterradius / Math.cos(circlesegmentangle / 2)
             var circlecenter = pointcoord.plus(midvector.times(radiuscorrected))
               // we don't need to create a full circle; a pie is enough. Find the angles for the pie:
             var startangle = alpha + midvector.angleRadians()
             var deltaangle = 2 * (Math.PI - alpha)
             var numsteps = 2 * Math.ceil(deltaangle / circlesegmentangle / 2) // should be even
               // build the pie:
             var points = [circlecenter]
             for (var i = 0; i <= numsteps; i++) {
               var angle = startangle + i / numsteps * deltaangle
               var p = CSG.Vector2D.fromAngleRadians(angle).times(radiuscorrected).plus(circlecenter)
               points.push(p)
             }
             cutouts.push(CAG.fromPoints(points))
           }
         }
       }
       var result = cag.subtract(cutouts)
       return result
     }
   }
   CAG.Vertex = function (pos) {
     this.pos = pos
   }
   CAG.Vertex.prototype = {
     toString: function () {
       return "(" + this.pos.x.toFixed(2) + "," + this.pos.y.toFixed(2) + ")"
     },
     getTag: function () {
       var result = this.tag
       if (!result) {
         result = CSG.getTag()
         this.tag = result
       }
       return result
     }
   }
   CAG.Side = function (vertex0, vertex1) {
     if (!(vertex0 instanceof CAG.Vertex)) throw new Error("Assertion failed")
     if (!(vertex1 instanceof CAG.Vertex)) throw new Error("Assertion failed")
     this.vertex0 = vertex0
     this.vertex1 = vertex1
   }
   CAG.Side._fromFakePolygon = function (polygon) {
     polygon.vertices.forEach(function (v) {
         if (!((v.pos.z >= -1.001) && (v.pos.z < -0.999)) && !((v.pos.z >= 0.999) && (v.pos.z < 1.001))) {
           throw ("Assertion failed: _fromFakePolygon expects abs z values of 1")
         }
       })
       // this can happen based on union, seems to be residuals -
       // return null and handle in caller
     if (polygon.vertices.length < 4) {
       return null
     }
     var reverse = false
     var vert1Indices = []
     var pts2d = polygon.vertices.filter(function (v, i) {
         if (v.pos.z > 0) {
           vert1Indices.push(i)
           return true
         }
       })
       .map(function (v) {
         return new CSG.Vector2D(v.pos.x, v.pos.y)
       })
     if (pts2d.length !== 2) {
       throw ('Assertion failed: _fromFakePolygon: not enough points found')
     }
     var d = vert1Indices[1] - vert1Indices[0]
     if (d === 1 || d === 3) {
       if (d === 1) {
         pts2d.reverse()
       }
     } else {
       throw ('Assertion failed: _fromFakePolygon: unknown index ordering')
     }
     var result = new CAG.Side(new CAG.Vertex(pts2d[0]), new CAG.Vertex(pts2d[1]))
     return result
   }
   CAG.Side.prototype = {
       toString: function () {
         return this.vertex0 + " -> " + this.vertex1
       },
       toPolygon3D: function (z0, z1) {
         var vertices = [
           new CSG.Vertex(this.vertex0.pos.toVector3D(z0)),
           new CSG.Vertex(this.vertex1.pos.toVector3D(z0)),
           new CSG.Vertex(this.vertex1.pos.toVector3D(z1)),
           new CSG.Vertex(this.vertex0.pos.toVector3D(z1))
         ]
         return new CSG.Polygon(vertices)
       },
       transform: function (matrix4x4) {
         var newp1 = this.vertex0.pos.transform(matrix4x4)
         var newp2 = this.vertex1.pos.transform(matrix4x4)
         return new CAG.Side(new CAG.Vertex(newp1), new CAG.Vertex(newp2))
       },
       flipped: function () {
         return new CAG.Side(this.vertex1, this.vertex0)
       },
       direction: function () {
         return this.vertex1.pos.minus(this.vertex0.pos)
       },
       getTag: function () {
         var result = this.tag
         if (!result) {
           result = CSG.getTag()
           this.tag = result
         }
         return result
       },
       lengthSquared: function () {
         var x = this.vertex1.pos.x - this.vertex0.pos.x,
           y = this.vertex1.pos.y - this.vertex0.pos.y
         return x * x + y * y
       },
       length: function () {
         return Math.sqrt(this.lengthSquared())
       }
     }
     //////////////////////////////////////
   CAG.fuzzyCAGFactory = function () {
     this.vertexfactory = new CSG.fuzzyFactory(2, 1e-5)
   }
   CAG.fuzzyCAGFactory.prototype = {
       getVertex: function (sourcevertex) {
         var elements = [sourcevertex.pos._x, sourcevertex.pos._y]
         var result = this.vertexfactory.lookupOrCreate(elements, function (els) {
           return sourcevertex
         })
         return result
       },
       getSide: function (sourceside) {
         var vertex0 = this.getVertex(sourceside.vertex0)
         var vertex1 = this.getVertex(sourceside.vertex1)
         return new CAG.Side(vertex0, vertex1)
       },
       getCAG: function (sourcecag) {
         var _this = this
         var newsides = sourcecag.sides.map(function (side) {
             return _this.getSide(side)
           })
           // remove bad sides (mostly a user input issue)
           .filter(function (side) {
             return side.length() > 1e-5
           })
         return CAG.fromSides(newsides)
       }
     }
     //////////////////////////////////////
   CSG.addTransformationMethodsToPrototype(CSG.prototype)
   CSG.addTransformationMethodsToPrototype(CSG.Vector2D.prototype)
   CSG.addTransformationMethodsToPrototype(CSG.Vector3D.prototype)
   CSG.addTransformationMethodsToPrototype(CSG.Vertex.prototype)
   CSG.addTransformationMethodsToPrototype(CSG.Plane.prototype)
   CSG.addTransformationMethodsToPrototype(CSG.Polygon.prototype)
   CSG.addTransformationMethodsToPrototype(CSG.Line3D.prototype)
   CSG.addTransformationMethodsToPrototype(CSG.Connector.prototype)
   CSG.addTransformationMethodsToPrototype(CSG.Path2D.prototype)
   CSG.addTransformationMethodsToPrototype(CSG.Line2D.prototype)
   CSG.addTransformationMethodsToPrototype(CAG.prototype)
   CSG.addTransformationMethodsToPrototype(CAG.Side.prototype)
   CSG.addTransformationMethodsToPrototype(CSG.OrthoNormalBasis.prototype)
   CSG.addCenteringToPrototype(CSG.prototype, ['x', 'y', 'z'])
   CSG.addCenteringToPrototype(CAG.prototype, ['x', 'y'])
   /*
   2D polygons are now supported through the CAG class.
   With many improvements (see documentation):
     - shapes do no longer have to be convex
     - union/intersect/subtract is supported
     - expand / contract are supported

   But we'll keep CSG.Polygon2D as a stub for backwards compatibility
   */
   CSG.Polygon2D = function (points) {
     var cag = CAG.fromPoints(points)
     this.sides = cag.sides
   }
   CSG.Polygon2D.prototype = CAG.prototype

   /* eslint-disable */
   // -- data below from http://paulbourke.net/dataformats/hershey/
   var simplexFont = [
       0,16, /* Ascii 32 */
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       8,10, /* Ascii 33 */
       5,21, 5, 7,-1,-1, 5, 2, 4, 1, 5, 0, 6, 1, 5, 2,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       5,16, /* Ascii 34 */
       4,21, 4,14,-1,-1,12,21,12,14,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      11,21, /* Ascii 35 */
      11,25, 4,-7,-1,-1,17,25,10,-7,-1,-1, 4,12,18,12,-1,-1, 3, 6,17, 6,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      26,20, /* Ascii 36 */
       8,25, 8,-4,-1,-1,12,25,12,-4,-1,-1,17,18,15,20,12,21, 8,21, 5,20, 3,
      18, 3,16, 4,14, 5,13, 7,12,13,10,15, 9,16, 8,17, 6,17, 3,15, 1,12, 0,
       8, 0, 5, 1, 3, 3,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      31,24, /* Ascii 37 */
      21,21, 3, 0,-1,-1, 8,21,10,19,10,17, 9,15, 7,14, 5,14, 3,16, 3,18, 4,
      20, 6,21, 8,21,10,20,13,19,16,19,19,20,21,21,-1,-1,17, 7,15, 6,14, 4,
      14, 2,16, 0,18, 0,20, 1,21, 3,21, 5,19, 7,17, 7,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      34,26, /* Ascii 38 */
      23,12,23,13,22,14,21,14,20,13,19,11,17, 6,15, 3,13, 1,11, 0, 7, 0, 5,
       1, 4, 2, 3, 4, 3, 6, 4, 8, 5, 9,12,13,13,14,14,16,14,18,13,20,11,21,
       9,20, 8,18, 8,16, 9,13,11,10,16, 3,18, 1,20, 0,22, 0,23, 1,23, 2,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       7,10, /* Ascii 39 */
       5,19, 4,20, 5,21, 6,20, 6,18, 5,16, 4,15,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      10,14, /* Ascii 40 */
      11,25, 9,23, 7,20, 5,16, 4,11, 4, 7, 5, 2, 7,-2, 9,-5,11,-7,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      10,14, /* Ascii 41 */
       3,25, 5,23, 7,20, 9,16,10,11,10, 7, 9, 2, 7,-2, 5,-5, 3,-7,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       8,16, /* Ascii 42 */
       8,21, 8, 9,-1,-1, 3,18,13,12,-1,-1,13,18, 3,12,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       5,26, /* Ascii 43 */
      13,18,13, 0,-1,-1, 4, 9,22, 9,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       8,10, /* Ascii 44 */
       6, 1, 5, 0, 4, 1, 5, 2, 6, 1, 6,-1, 5,-3, 4,-4,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       2,26, /* Ascii 45 */
       4, 9,22, 9,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       5,10, /* Ascii 46 */
       5, 2, 4, 1, 5, 0, 6, 1, 5, 2,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       2,22, /* Ascii 47 */
      20,25, 2,-7,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      17,20, /* Ascii 48 */
       9,21, 6,20, 4,17, 3,12, 3, 9, 4, 4, 6, 1, 9, 0,11, 0,14, 1,16, 4,17,
       9,17,12,16,17,14,20,11,21, 9,21,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       4,20, /* Ascii 49 */
       6,17, 8,18,11,21,11, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      14,20, /* Ascii 50 */
       4,16, 4,17, 5,19, 6,20, 8,21,12,21,14,20,15,19,16,17,16,15,15,13,13,
      10, 3, 0,17, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      15,20, /* Ascii 51 */
       5,21,16,21,10,13,13,13,15,12,16,11,17, 8,17, 6,16, 3,14, 1,11, 0, 8,
       0, 5, 1, 4, 2, 3, 4,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       6,20, /* Ascii 52 */
      13,21, 3, 7,18, 7,-1,-1,13,21,13, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      17,20, /* Ascii 53 */
      15,21, 5,21, 4,12, 5,13, 8,14,11,14,14,13,16,11,17, 8,17, 6,16, 3,14,
       1,11, 0, 8, 0, 5, 1, 4, 2, 3, 4,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      23,20, /* Ascii 54 */
      16,18,15,20,12,21,10,21, 7,20, 5,17, 4,12, 4, 7, 5, 3, 7, 1,10, 0,11,
       0,14, 1,16, 3,17, 6,17, 7,16,10,14,12,11,13,10,13, 7,12, 5,10, 4, 7,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       5,20, /* Ascii 55 */
      17,21, 7, 0,-1,-1, 3,21,17,21,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      29,20, /* Ascii 56 */
       8,21, 5,20, 4,18, 4,16, 5,14, 7,13,11,12,14,11,16, 9,17, 7,17, 4,16,
       2,15, 1,12, 0, 8, 0, 5, 1, 4, 2, 3, 4, 3, 7, 4, 9, 6,11, 9,12,13,13,
      15,14,16,16,16,18,15,20,12,21, 8,21,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      23,20, /* Ascii 57 */
      16,14,15,11,13, 9,10, 8, 9, 8, 6, 9, 4,11, 3,14, 3,15, 4,18, 6,20, 9,
      21,10,21,13,20,15,18,16,14,16, 9,15, 4,13, 1,10, 0, 8, 0, 5, 1, 4, 3,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      11,10, /* Ascii 58 */
       5,14, 4,13, 5,12, 6,13, 5,14,-1,-1, 5, 2, 4, 1, 5, 0, 6, 1, 5, 2,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      14,10, /* Ascii 59 */
       5,14, 4,13, 5,12, 6,13, 5,14,-1,-1, 6, 1, 5, 0, 4, 1, 5, 2, 6, 1, 6,
      -1, 5,-3, 4,-4,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       3,24, /* Ascii 60 */
      20,18, 4, 9,20, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       5,26, /* Ascii 61 */
       4,12,22,12,-1,-1, 4, 6,22, 6,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       3,24, /* Ascii 62 */
       4,18,20, 9, 4, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      20,18, /* Ascii 63 */
       3,16, 3,17, 4,19, 5,20, 7,21,11,21,13,20,14,19,15,17,15,15,14,13,13,
      12, 9,10, 9, 7,-1,-1, 9, 2, 8, 1, 9, 0,10, 1, 9, 2,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      55,27, /* Ascii 64 */
      18,13,17,15,15,16,12,16,10,15, 9,14, 8,11, 8, 8, 9, 6,11, 5,14, 5,16,
       6,17, 8,-1,-1,12,16,10,14, 9,11, 9, 8,10, 6,11, 5,-1,-1,18,16,17, 8,
      17, 6,19, 5,21, 5,23, 7,24,10,24,12,23,15,22,17,20,19,18,20,15,21,12,
      21, 9,20, 7,19, 5,17, 4,15, 3,12, 3, 9, 4, 6, 5, 4, 7, 2, 9, 1,12, 0,
      15, 0,18, 1,20, 2,21, 3,-1,-1,19,16,18, 8,18, 6,19, 5,
       8,18, /* Ascii 65 */
       9,21, 1, 0,-1,-1, 9,21,17, 0,-1,-1, 4, 7,14, 7,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      23,21, /* Ascii 66 */
       4,21, 4, 0,-1,-1, 4,21,13,21,16,20,17,19,18,17,18,15,17,13,16,12,13,
      11,-1,-1, 4,11,13,11,16,10,17, 9,18, 7,18, 4,17, 2,16, 1,13, 0, 4, 0,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      18,21, /* Ascii 67 */
      18,16,17,18,15,20,13,21, 9,21, 7,20, 5,18, 4,16, 3,13, 3, 8, 4, 5, 5,
       3, 7, 1, 9, 0,13, 0,15, 1,17, 3,18, 5,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      15,21, /* Ascii 68 */
       4,21, 4, 0,-1,-1, 4,21,11,21,14,20,16,18,17,16,18,13,18, 8,17, 5,16,
       3,14, 1,11, 0, 4, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      11,19, /* Ascii 69 */
       4,21, 4, 0,-1,-1, 4,21,17,21,-1,-1, 4,11,12,11,-1,-1, 4, 0,17, 0,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       8,18, /* Ascii 70 */
       4,21, 4, 0,-1,-1, 4,21,17,21,-1,-1, 4,11,12,11,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      22,21, /* Ascii 71 */
      18,16,17,18,15,20,13,21, 9,21, 7,20, 5,18, 4,16, 3,13, 3, 8, 4, 5, 5,
       3, 7, 1, 9, 0,13, 0,15, 1,17, 3,18, 5,18, 8,-1,-1,13, 8,18, 8,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       8,22, /* Ascii 72 */
       4,21, 4, 0,-1,-1,18,21,18, 0,-1,-1, 4,11,18,11,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       2, 8, /* Ascii 73 */
       4,21, 4, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      10,16, /* Ascii 74 */
      12,21,12, 5,11, 2,10, 1, 8, 0, 6, 0, 4, 1, 3, 2, 2, 5, 2, 7,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       8,21, /* Ascii 75 */
       4,21, 4, 0,-1,-1,18,21, 4, 7,-1,-1, 9,12,18, 0,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       5,17, /* Ascii 76 */
       4,21, 4, 0,-1,-1, 4, 0,16, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      11,24, /* Ascii 77 */
       4,21, 4, 0,-1,-1, 4,21,12, 0,-1,-1,20,21,12, 0,-1,-1,20,21,20, 0,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       8,22, /* Ascii 78 */
       4,21, 4, 0,-1,-1, 4,21,18, 0,-1,-1,18,21,18, 0,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      21,22, /* Ascii 79 */
       9,21, 7,20, 5,18, 4,16, 3,13, 3, 8, 4, 5, 5, 3, 7, 1, 9, 0,13, 0,15,
       1,17, 3,18, 5,19, 8,19,13,18,16,17,18,15,20,13,21, 9,21,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      13,21, /* Ascii 80 */
       4,21, 4, 0,-1,-1, 4,21,13,21,16,20,17,19,18,17,18,14,17,12,16,11,13,
      10, 4,10,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      24,22, /* Ascii 81 */
       9,21, 7,20, 5,18, 4,16, 3,13, 3, 8, 4, 5, 5, 3, 7, 1, 9, 0,13, 0,15,
       1,17, 3,18, 5,19, 8,19,13,18,16,17,18,15,20,13,21, 9,21,-1,-1,12, 4,
      18,-2,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      16,21, /* Ascii 82 */
       4,21, 4, 0,-1,-1, 4,21,13,21,16,20,17,19,18,17,18,15,17,13,16,12,13,
      11, 4,11,-1,-1,11,11,18, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      20,20, /* Ascii 83 */
      17,18,15,20,12,21, 8,21, 5,20, 3,18, 3,16, 4,14, 5,13, 7,12,13,10,15,
       9,16, 8,17, 6,17, 3,15, 1,12, 0, 8, 0, 5, 1, 3, 3,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       5,16, /* Ascii 84 */
       8,21, 8, 0,-1,-1, 1,21,15,21,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      10,22, /* Ascii 85 */
       4,21, 4, 6, 5, 3, 7, 1,10, 0,12, 0,15, 1,17, 3,18, 6,18,21,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       5,18, /* Ascii 86 */
       1,21, 9, 0,-1,-1,17,21, 9, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      11,24, /* Ascii 87 */
       2,21, 7, 0,-1,-1,12,21, 7, 0,-1,-1,12,21,17, 0,-1,-1,22,21,17, 0,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       5,20, /* Ascii 88 */
       3,21,17, 0,-1,-1,17,21, 3, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       6,18, /* Ascii 89 */
       1,21, 9,11, 9, 0,-1,-1,17,21, 9,11,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       8,20, /* Ascii 90 */
      17,21, 3, 0,-1,-1, 3,21,17,21,-1,-1, 3, 0,17, 0,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      11,14, /* Ascii 91 */
       4,25, 4,-7,-1,-1, 5,25, 5,-7,-1,-1, 4,25,11,25,-1,-1, 4,-7,11,-7,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       2,14, /* Ascii 92 */
       0,21,14,-3,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      11,14, /* Ascii 93 */
       9,25, 9,-7,-1,-1,10,25,10,-7,-1,-1, 3,25,10,25,-1,-1, 3,-7,10,-7,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      10,16, /* Ascii 94 */
       6,15, 8,18,10,15,-1,-1, 3,12, 8,17,13,12,-1,-1, 8,17, 8, 0,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       2,16, /* Ascii 95 */
       0,-2,16,-2,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       7,10, /* Ascii 96 */
       6,21, 5,20, 4,18, 4,16, 5,15, 6,16, 5,17,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      17,19, /* Ascii 97 */
      15,14,15, 0,-1,-1,15,11,13,13,11,14, 8,14, 6,13, 4,11, 3, 8, 3, 6, 4,
       3, 6, 1, 8, 0,11, 0,13, 1,15, 3,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      17,19, /* Ascii 98 */
       4,21, 4, 0,-1,-1, 4,11, 6,13, 8,14,11,14,13,13,15,11,16, 8,16, 6,15,
       3,13, 1,11, 0, 8, 0, 6, 1, 4, 3,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      14,18, /* Ascii 99 */
      15,11,13,13,11,14, 8,14, 6,13, 4,11, 3, 8, 3, 6, 4, 3, 6, 1, 8, 0,11,
       0,13, 1,15, 3,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      17,19, /* Ascii 100 */
      15,21,15, 0,-1,-1,15,11,13,13,11,14, 8,14, 6,13, 4,11, 3, 8, 3, 6, 4,
       3, 6, 1, 8, 0,11, 0,13, 1,15, 3,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      17,18, /* Ascii 101 */
       3, 8,15, 8,15,10,14,12,13,13,11,14, 8,14, 6,13, 4,11, 3, 8, 3, 6, 4,
       3, 6, 1, 8, 0,11, 0,13, 1,15, 3,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       8,12, /* Ascii 102 */
      10,21, 8,21, 6,20, 5,17, 5, 0,-1,-1, 2,14, 9,14,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      22,19, /* Ascii 103 */
      15,14,15,-2,14,-5,13,-6,11,-7, 8,-7, 6,-6,-1,-1,15,11,13,13,11,14, 8,
      14, 6,13, 4,11, 3, 8, 3, 6, 4, 3, 6, 1, 8, 0,11, 0,13, 1,15, 3,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      10,19, /* Ascii 104 */
       4,21, 4, 0,-1,-1, 4,10, 7,13, 9,14,12,14,14,13,15,10,15, 0,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       8, 8, /* Ascii 105 */
       3,21, 4,20, 5,21, 4,22, 3,21,-1,-1, 4,14, 4, 0,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      11,10, /* Ascii 106 */
       5,21, 6,20, 7,21, 6,22, 5,21,-1,-1, 6,14, 6,-3, 5,-6, 3,-7, 1,-7,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       8,17, /* Ascii 107 */
       4,21, 4, 0,-1,-1,14,14, 4, 4,-1,-1, 8, 8,15, 0,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       2, 8, /* Ascii 108 */
       4,21, 4, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      18,30, /* Ascii 109 */
       4,14, 4, 0,-1,-1, 4,10, 7,13, 9,14,12,14,14,13,15,10,15, 0,-1,-1,15,
      10,18,13,20,14,23,14,25,13,26,10,26, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      10,19, /* Ascii 110 */
       4,14, 4, 0,-1,-1, 4,10, 7,13, 9,14,12,14,14,13,15,10,15, 0,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      17,19, /* Ascii 111 */
       8,14, 6,13, 4,11, 3, 8, 3, 6, 4, 3, 6, 1, 8, 0,11, 0,13, 1,15, 3,16,
       6,16, 8,15,11,13,13,11,14, 8,14,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      17,19, /* Ascii 112 */
       4,14, 4,-7,-1,-1, 4,11, 6,13, 8,14,11,14,13,13,15,11,16, 8,16, 6,15,
       3,13, 1,11, 0, 8, 0, 6, 1, 4, 3,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      17,19, /* Ascii 113 */
      15,14,15,-7,-1,-1,15,11,13,13,11,14, 8,14, 6,13, 4,11, 3, 8, 3, 6, 4,
       3, 6, 1, 8, 0,11, 0,13, 1,15, 3,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       8,13, /* Ascii 114 */
       4,14, 4, 0,-1,-1, 4, 8, 5,11, 7,13, 9,14,12,14,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      17,17, /* Ascii 115 */
      14,11,13,13,10,14, 7,14, 4,13, 3,11, 4, 9, 6, 8,11, 7,13, 6,14, 4,14,
       3,13, 1,10, 0, 7, 0, 4, 1, 3, 3,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       8,12, /* Ascii 116 */
       5,21, 5, 4, 6, 1, 8, 0,10, 0,-1,-1, 2,14, 9,14,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      10,19, /* Ascii 117 */
       4,14, 4, 4, 5, 1, 7, 0,10, 0,12, 1,15, 4,-1,-1,15,14,15, 0,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       5,16, /* Ascii 118 */
       2,14, 8, 0,-1,-1,14,14, 8, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      11,22, /* Ascii 119 */
       3,14, 7, 0,-1,-1,11,14, 7, 0,-1,-1,11,14,15, 0,-1,-1,19,14,15, 0,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       5,17, /* Ascii 120 */
       3,14,14, 0,-1,-1,14,14, 3, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       9,16, /* Ascii 121 */
       2,14, 8, 0,-1,-1,14,14, 8, 0, 6,-4, 4,-6, 2,-7, 1,-7,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       8,17, /* Ascii 122 */
      14,14, 3, 0,-1,-1, 3,14,14,14,-1,-1, 3, 0,14, 0,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      39,14, /* Ascii 123 */
       9,25, 7,24, 6,23, 5,21, 5,19, 6,17, 7,16, 8,14, 8,12, 6,10,-1,-1, 7,
      24, 6,22, 6,20, 7,18, 8,17, 9,15, 9,13, 8,11, 4, 9, 8, 7, 9, 5, 9, 3,
       8, 1, 7, 0, 6,-2, 6,-4, 7,-6,-1,-1, 6, 8, 8, 6, 8, 4, 7, 2, 6, 1, 5,
      -1, 5,-3, 6,-5, 7,-6, 9,-7,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
       2, 8, /* Ascii 124 */
       4,25, 4,-7,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      39,14, /* Ascii 125 */
       5,25, 7,24, 8,23, 9,21, 9,19, 8,17, 7,16, 6,14, 6,12, 8,10,-1,-1, 7,
      24, 8,22, 8,20, 7,18, 6,17, 5,15, 5,13, 6,11,10, 9, 6, 7, 5, 5, 5, 3,
       6, 1, 7, 0, 8,-2, 8,-4, 7,-6,-1,-1, 8, 8, 6, 6, 6, 4, 7, 2, 8, 1, 9,
      -1, 9,-3, 8,-5, 7,-6, 5,-7,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      23,24, /* Ascii 126 */
       3, 6, 3, 8, 4,11, 6,12, 8,12,10,11,14, 8,16, 7,18, 7,20, 8,21,10,-1,
      -1, 3, 8, 4,10, 6,11, 8,11,10,10,14, 7,16, 6,18, 6,20, 7,21,10,21,12,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
      -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
   ]

   /*
    adapted from THREE.CSG
    @author Chandler Prall <chandler.prall@gmail.com> http://chandler.prallfamily.com
    Wrapper for Evan Wallace's CSG library (https://github.com/evanw/csg.js/)
    Provides CSG capabilities for Three.js models.
    Provided under the MIT License
   */
   var index = (function () {
    var THREE
    // check dependency
    if (window.THREE) {
      THREE = window.THREE
    } else if (global.THREE) {
      THREE = global.THREE
    } else {
      global.throw("THREE is undefined, please include THREE.js")
    }

    THREE.CSG = CSG
    /**
     * Construct a CSG solid from a `THREE.Geometry` instance.
     *
     * @method fromGeometry
     * @return CSG instance
     */
    THREE.CSG.fromGeometry = function (geometry) {
      var polygons = []
      if (geometry instanceof THREE.BufferGeometry) {
       geometry = new THREE.Geometry().fromBufferGeometry(geometry)
      }
      for (var i = 0; i < geometry.faces.length; i++) {
        var face = geometry.faces[i]
        var pos
        var vertex
        var vertices = []
        var polygon

        if (face instanceof THREE.Face3) {
          vertex = geometry.vertices[face.a]
          pos = new CSG.Vector3D(vertex.x, vertex.y, vertex.z)
          vertices.push(new CSG.Vertex(pos))

          vertex = geometry.vertices[face.b]
          pos = new CSG.Vector3D(vertex.x, vertex.y, vertex.z)
          vertices.push(new CSG.Vertex(pos))

          vertex = geometry.vertices[face.c]
          pos = new CSG.Vector3D(vertex.x, vertex.y, vertex.z)
          vertices.push(new CSG.Vertex(pos))
        } else if (face instanceof THREE.Face4) {
          vertex = geometry.vertices[face.a]
          pos = new CSG.Vector3D(vertex.x, vertex.y, vertex.z)
          vertices.push(new CSG.Vertex(pos))

          vertex = geometry.vertices[face.b]
          pos = new CSG.Vector3D(vertex.x, vertex.y, vertex.z)
          vertices.push(new CSG.Vertex(pos))

          vertex = geometry.vertices[face.c]
          pos = new CSG.Vector3D(vertex.x, vertex.y, vertex.z)
          vertices.push(new CSG.Vertex(pos))

          vertex = geometry.vertices[face.d]
          pos = new CSG.Vector3D(vertex.x, vertex.y, vertex.z)
          vertices.push(new CSG.Vertex(pos))
        } else {
         throw 'Invalid face type at index ' + i
        }

        polygon = new CSG.Polygon(vertices)
        if (polygon.checkIfConvex()==true) // throw a error if not convex
        polygons.push(polygon)
      }
      return CSG.fromPolygons(polygons)
    }

    /**
     * Construct a CSG solid from a `THREE.Mesh` instance.
     *
     * @method fromMesh
     * @return CSG instance
     */
    THREE.CSG.fromMesh = function (mesh) {
      mesh.updateMatrix()
      this.matrix = new CSG.Matrix4x4(mesh.matrix.clone().elements)
      var _geometry
      if (mesh.geometry instanceof THREE.BufferGeometry) {
       _geometry = new THREE.Geometry().fromBufferGeometry(mesh.geometry)
      } else {
       _geometry = mesh.geometry
      }
      var csg = THREE.CSG.fromGeometry(_geometry)
      return csg.transform(this.matrix)
    }

    THREE.CSG.fromText = function (text, parameters) {
      var polylines = vector_text(0, 0, text)
      var o = []
      var weight = parameters.weight || 3 // Weight of font. Default is 3
      var height = parameters.height || 5 // Thickness to extrude text. Default is 5
      var size = parameters.size || 20 // font size. Default is 20

      polylines.forEach(function (pl) {
        o.push(rectangular_extrude(pl, {w: weight, h: height}))
      })

      var csg = new CSG().union(o)
      csg = csg.scale(size / 20)
      return csg
    }

    THREE.CSG.resultFromCompactBinary = function (resultin) {
      function fromCompactBinary (r) {
        var result
        if (r.class === 'CSG') {
          result = CSG.fromCompactBinary(r)
        } else {
          throw new Error('Cannot parse result')
        }
        return result
      }
      var resultout
      if (resultin instanceof Array) {
        resultout = resultin.map(function (resultelement) {
          var r = resultelement
          r = fromCompactBinary(resultelement)
          return r
        })
      } else {
        resultout = fromCompactBinary(resultin)
      }
      return resultout
    }

    THREE.CSG.resultToCompactBinary = function (resultin) {
      var resultout
      if (resultin instanceof Array) {
        resultout = resultin.map(function (resultelement) {
          var r = resultelement
          r = resultelement.toCompactBinary()
          return r
        })
      } else {
        resultout = resultin.toCompactBinary()
      }
      return resultout
    }

    // convert CSG object to three.js geometry.
    THREE.CSG.toGeometry = function (csg) {
      var face
      var three_geometry = new THREE.Geometry()
      var polygons = csg.toPolygons()

      polygons.forEach(function (polygon) {
        var vertices = polygon.vertices.map(function (vertex) {
          return getGeometryVertex(three_geometry, vertex.pos)
        }, this)

        if (vertices[0] === vertices[vertices.length - 1]) {
          vertices.pop()
        }

        for (var i = 2; i < vertices.length; i++) {
          face = new THREE.Face3(vertices[0], vertices[i - 1], vertices[i], new THREE.Vector3().copy(polygon.plane.normal))
          three_geometry.faces.push(face)
        }
      }, this)

      return three_geometry
    }

    // convert CSG object to three.js mesh.
    THREE.CSG.toMesh = function (csg, material) {
      var three_geometry = THREE.CSG.toGeometry(csg)
      var three_mesh = new THREE.Mesh(three_geometry, material)
      return three_mesh
    }

    function getGeometryVertex (geometry, vertex_position) {
      geometry.vertices.push(new THREE.Vector3(vertex_position.x, vertex_position.y, vertex_position.z))
      return geometry.vertices.length - 1
    }

    function rectangular_extrude (pa, p) {
      var w = 1
      var h = 1
      var fn = 8
      var closed = false
      var round = true
      if (p) {
        if (p.w) w = p.w
        if (p.h) h = p.h
        if (p.fn) fn = p.fn
        if (p.closed !== undefined) closed = p.closed
        if (p.round !== undefined) round = p.round
      }
      return new CSG.Path2D(pa, closed).rectangularExtrude(w, h, fn, round)
    }

    function vector_char (x, y, c) {
      c = c.charCodeAt(0)
      c -= 32
      if (c < 0 || c >= 95) {
        return {
          width: 0,
          segments: []
        }
      }
      var off = c * 112
      var n = simplexFont[off++]
      var w = simplexFont[off++]
      var l = []
      var segs = []
      for (var i = 0; i < n; i++) {
        var xp = simplexFont[off + i * 2]
        var yp = simplexFont[off + i * 2 + 1]
        if (xp === -1 && yp === -1) {
          segs.push(l)
          l = []
        } else {
          l.push([xp + x, yp + y])
        }
      }
      if (l.length) segs.push(l)
      return {
        width: w,
        segments: segs
      }
    }

    function vector_text (x, y, s) {
      var o = []
      var x0 = x
      for (var i = 0; i < s.length; i++) {
        var c = s.charAt(i)
        if (c === '\n') {
          x = x0
          y -= 30
        } else {
          var d = vector_char(x, y, c)
          x += d.width
          o = o.concat(d.segments)
        }
      }
      return o
    }
   })()

   return index;

}());