Wolfram Demonstrations Projecthttp://demonstrations.wolfram.com/An Open Resource of Interactive Mathematica VisualizationsCopyright 2009 Wolfram Demonstrations Project & ContributorsSpirographic Orbit of a Star in Extended Mass Distributionhttp://demonstrations.wolfram.com/SpirographicOrbitOfAStarInExtendedMassDistribution/]]>http://demonstrations.wolfram.com/SpirographicOrbitOfAStarInExtendedMassDistribution/