MDDN 241: Clockwork & Bubbles

I have chosen to go with my second idea, which involves a bubble floating up and then hardening into stone. The stone will then fall down and crack open to reveal clockwork-like mechanisms.

Here are a couple of examples of the inner workings of pocket watches, which is similar to the sort of thing that I want to do.

I also found a Maya tutorial which shows you how to make a bubble.