Graphing Calculators
http://wabbit.codeplex.com/releases/view/44625
https://www.desmos.com/calculator
http://my.hrw.com/math06_07/nsmedia/tools/Graph_Calculator/graphCalc.html
http://www.fooplot.com/#W3sidHlwZSI6MCwiZXEiOiJ4XjIiLCJjb2xvciI6IiMwMDAwMDAifSx7InR5cGUiOjEwMDB9XQ--