Interactive Epicycloids
Intetractive version of the rolling epicycloids described by John Baez (and others) at:
http://johncarlosbaez.wordpress.com/2013/12/03/rolling-hypocycloids/#comment-34678
Javascript and GeoGebra versions at:
http://www.malinc.se/m/RollingHypocycloids.php
Move the white dots!