Somewhat generic, but I'll try.
The red thing at the bottom of the claw mechanism is the "computer" that calculates where the mouse is in relation to it. It then adjusts the length of the spring or the speed of the hinges up top to try and follow the mouse.
Dare, I know you probably want to make some comment about using gradients and all that. Please don't. We've all heard it. Frozer explicitly said no textures, and I think that's fine.