Final evolution of my cycloid sketches. Let's you experiment with spirograph style mathematical art, which relies on understanding of gears & fractions and circle geometry, and can extend to trigonometry and parametric functions.
Cf. http://en.wikipedia.org/wiki/Cycloid, http://en.wikipedia.org/wiki/Trochoid, and http://en.wikipedia.org/wiki/Spirograph
Simpler previous sketches: Hypocycloid: http://www.geogebratube.org/material/show/id/29156 (inner rolling), Cycloid: http://www.geogebratube.org/material/show/id/29352 (choice of inner and outer).
Let me know if there are any more features desired!
