Wolfram Demonstrations Projecthttp://demonstrations.wolfram.com/An Open Resource of Interactive Mathematica VisualizationsCopyright 2009 Wolfram Demonstrations Project & ContributorsThe Hopping Frog Word Problem for Rate, d = r thttp://demonstrations.wolfram.com/TheHoppingFrogWordProblemForRateDRT/]]>http://demonstrations.wolfram.com/TheHoppingFrogWordProblemForRateDRT/Two Trains Puzzlehttp://demonstrations.wolfram.com/TwoTrainsPuzzle/]]>http://demonstrations.wolfram.com/TwoTrainsPuzzle/