I am not very good at mechanics, but trying to figure out the trajectory of the patting element feels like it wouldn't move as one might expect. The small wheel is going to turn about 3,5 times while the big wheel turns once, and it looks like the device will get dead locked as soon as the piston's pivot point on the big wheel rotates close enough to the small wheel. The only possible way to use it is to constantly switch between spinning forwards and backwards.
Of course, all of these problems pale in comparison to the hedgehog and the wasp. But still.
