Algodoo

Instructions are in the scene. Phun users can change roller or tooth count by setting scene.my.count in the console (F11).

No polygons used in construction of chain or sprocket in order to minimize collision calculations. Remote hinge chains work OK but may break if you try to move just one link in design mode. If you select one chain circle with hinge and one of the adjacent hinges (only one of the two adjacent hinges will work for this), then you can "Use as chain" to make a chain of any length. The easiest way to connect a custom chain is to place the last hinge over the first when creating.