Press left and right to change the amount of rotation.
Just playing around with Archimedean spirals: http://en.wikipedia.org/wiki/Archimedean_spiral Does anyone know why some gaps appear? There are no gaps on phosphorus: http://phosphorus.github.io/#56047412 Edit: I fixed the bug. Explaination here: https://scratch.mit.edu/discuss/topic/105340/?page=1#post-920512