Revised version of a November 2011 Feature Column on the AMS website. The underlying technologies changed and so tweaks had to be made in order that it function as intended, and, indeed, how it used to. I kept an older version if you want to see it.
Note these demonstrations use the Geometer Sketchpad Java applet, so they will not display in Google's Chrome browser after Version 42, or in any other browser which does not have a modern Java plugin activated.
[Last Modified: Sunday, 12-Sep-2016 12:35:47 EDT]