Wolfram Demonstrations Projecthttp://demonstrations.wolfram.com/An Open Resource of Interactive Mathematica VisualizationsCopyright 2009 Wolfram Demonstrations Project & ContributorsEvaluate Hot Pizzahttp://demonstrations.wolfram.com/EvaluateHotPizza/]]>http://demonstrations.wolfram.com/EvaluateHotPizza/Proportional Quantitieshttp://demonstrations.wolfram.com/ProportionalQuantities/]]>http://demonstrations.wolfram.com/ProportionalQuantities/