Algodoo

You would SERIOUSLY cut down on lag by changing those outer circles to hinged wheels. Even in Algodoo, which has an algorithm to reduce the number of contacts in those situations, there are more collisions than I can count. Each circle has about thirteen contacts with the outer ring, and there are thirty-two circles. That makes for about 416 contacts at any given moment just from those little bearings. Contacts are rather laggy. Ever try an elastic collision out on paper? Two pages of work filled with square roots and stuff. Very taxing on the computer.