Dot Disc
Saw an image on Tumblr that had me curious... what makes the spiral effect?
Inspiration: http://beautyandthemaths.tumblr.com/post/89959942948
Gifs at: http://mathhombre.tumblr.com/post/89990751944/dot-disc-inspired-by-that-second-image-from-the
More GeoGebra at mathhombre.blogspot.com/p/geogebra.html