Three or four cats strapped together would give a much smoother rotation... there must be a way to strap a heap of cats to a wheel, where the driving force is gravity = free & clean power!!! One of these setups under the hood would be cool, damn cheap running costs and you'd be the first person in the world that can actually say that "she purr's like a kitten" They'd probably sound like 50 cats having sex actually
Pfft, no one got the obvious solution: Cut off it's paws! (I jest.. really!) Another vote for the water bottle.