Wolfram Demonstrations Projecthttp://demonstrations.wolfram.com/An Open Resource of Interactive Mathematica VisualizationsCopyright 2009 Wolfram Demonstrations Project & ContributorsA Test for the Convexity of a Quadrilateralhttp://demonstrations.wolfram.com/ATestForTheConvexityOfAQuadrilateral/]]>http://demonstrations.wolfram.com/ATestForTheConvexityOfAQuadrilateral/Polygon Spiralshttp://demonstrations.wolfram.com/PolygonSpirals/]]>http://demonstrations.wolfram.com/PolygonSpirals/Nested Regular Polygonshttp://demonstrations.wolfram.com/NestedRegularPolygons/]]>http://demonstrations.wolfram.com/NestedRegularPolygons/The Colorit Puzzlehttp://demonstrations.wolfram.com/TheColoritPuzzle/]]>http://demonstrations.wolfram.com/TheColoritPuzzle/How Many Triangles Are There?http://demonstrations.wolfram.com/HowManyTrianglesAreThere/]]>http://demonstrations.wolfram.com/HowManyTrianglesAreThere/Drawing a Colored Polygonhttp://demonstrations.wolfram.com/DrawingAColoredPolygon/]]>http://demonstrations.wolfram.com/DrawingAColoredPolygon/Geometrical Dollhttp://demonstrations.wolfram.com/GeometricalDoll/]]>http://demonstrations.wolfram.com/GeometricalDoll/