Copyright 2010 Kevin Ryde This file is part of Math-PlanePath. Math-PlanePath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. Math-PlanePath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with Math-PlanePath. If not, see . Version 3, July 2010 - new PyramidSpiral, TriangleSpiral, TriangleSpiralSkewed, PentSpiralSkewed Version 2, July 2010 - in Diagonals don't negative sqrt() if n=0 Version 1, July 2010 - the first version