Need help with 7th Grade Science Fair Project

[Patrick del Poker Grande]

This actually reminded me of another thing usually seen at the same kind of store you'd see the crazy dragon thing at. It wouldn't make much of a project on its own, but it could be incorporated into a project about optical illusions. It's that thing that's rigged up so it looks like a ball is rolling uphill when you let it go. Do you know what I'm talking about? It's just a dumb little desk ornament type thing, but it's cool.