Wolfram Demonstrations Projecthttp://demonstrations.wolfram.com/An Open Resource of Interactive Mathematica VisualizationsCopyright 2009 Wolfram Demonstrations Project & ContributorsPlanar Stress Rotationhttp://demonstrations.wolfram.com/PlanarStressRotation/]]>http://demonstrations.wolfram.com/PlanarStressRotation/Helix Staircase Plotterhttp://demonstrations.wolfram.com/HelixStaircasePlotter/]]>http://demonstrations.wolfram.com/HelixStaircasePlotter/