In about 5 minutes, one of my students figured out a clever way to make an in-game timer using linked buttons and cube droppers.
Interestingly, the student who made it has poor communication skills. I had trouble following his explanation of what he had in mind, yet he clearly knew what he was talking about. The Puzzle Maker gives students like him the opportunity to show what they know in a totally unique way, that is, for some students, more natural than traditional communication.
Physics with Portals 