GeoGebra version of Rolling Hypocycloids

as described by John Baez, Gerard Westendorp, and commenters at:
http://johncarlosbaez.wordpress.com/2013/12/03/rolling-hypocycloids/

GeoGebra Worksheet at GeoGebraTube:
http://www.geogebratube.org/student/m104067

Edit: Interactive version as suggested by +Boris Borcic :
http://www.geogebratube.org/material/show/id/105403