Algodoo

Easy but fast (maybe the fastest in the Algobox history!).
Scene.my.variables free!
C-Geared.
It reaches speeds of 20 rad/s when accelerating, and by the C-Gears, it uses most of the spawned circle energy!
Press RETURN to use the starter, and then UP to accelerate, if you want. It may speed up like 7 or 8 rad/s more.
In Update 1, I improved the stability of the engine. Faster than this? No way!
In Update 1.5, I made the engine moveable! And some minor things too.