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

Move the white dot!