It looks like there is more than one circle (at some times) that is going a different speed than the rotor (except at some times when it stops), but if you go in the sprite, you'll see that there is only one sprite, and is actually going the same speed as the rotor. Press 1 and 2 to toggle different illusions, 2 looks like the stick attached to the ball is detached from the rotor, even though it's connected to the rotor if you look inside and see the sprite.
it also appears (when the rotor is going fast) that it is rotating in the direction you're looking (e.g if you are looking to the left, the rotor rotates to the left, and vice versa.) (the circle appears to either match speed, or go faster than the rotor) I don't understand why it acts this way, but I think it's pretty cool.
