Implemented in CDF (Computational data format) using Mathematica.
To run this simulation inside the browser, a free plugin needs to be installed first. The plugin can be downloaded from the Wolfram research (Mathematica) web site http://www.wolfram.com/cdf-player/
Once the plugin is installed on your PC, then you should be able to interact with this simulation (you might want to refresh this page or restart the browser to make sure the plugin is active).
