Move and rotate rolling epicycloids
An interactive version of the rolling epicycloids described by John Baez (and others) at:
http://johncarlosbaez.wordpress.com/2013/12/03/rolling-hypocycloids/
Javascript and GeoGebra versions at:
http://www.malinc.se/m/RollingHypocycloids.php
In order to fit inside each other, each epicycloid rotates around a point that lies on the periphery of a circle whose midpoint is the centre of the next (larger) epicycloid.