Wolfram Demonstrations Projecthttp://demonstrations.wolfram.com/An Open Resource of Interactive Mathematica VisualizationsCopyright 2009 Wolfram Demonstrations Project & ContributorsCounting by Stepshttp://demonstrations.wolfram.com/CountingBySteps/]]>http://demonstrations.wolfram.com/CountingBySteps/Zigzagging Over Tables of Numbershttp://demonstrations.wolfram.com/ZigzaggingOverTablesOfNumbers/]]>http://demonstrations.wolfram.com/ZigzaggingOverTablesOfNumbers/