Hi, okay, I'm really confused. What qualifies a revolution? How do we know that it has done one by the time it is at the bottom of the coin? Just because the coin is right side up at the bottom doesn't mean it has revolved completely (does it?). The way I see it is from the center coin's perspective; first it is being touched by the Queen's neck, then her face, then her hair, then the back of her head, and finally her neck again. But that leaves us at the start, causing me to think that it has really only performed one revolution. But obviously I'm wrong. Please can someone explain where I've gone wrong. Thanks.