I call this my "Wonderbread" graph for, I hope, obvious reasons.
I had it posted online before done in Geometer's Sketchpad, but I had an error in the captions. Rather than fix that (since I no longer use costly Sketchpad) I have merely recreated it in Geogebra. The point on the smaller circle rotates three times as fast as the point on the larger circles.
It is just another example in my quest to convince educators and parents that guided explorations with software such as GeoGebra can be a prelude to, and a motivator for, standard mathematics education in school.
To deny young students such hands-on experimentation is to do a great disservice.
The complete file is available at http://tube.geogebra.org/material/show/id/1374049