Handshouse Studio have a site that’s worth looking at. They’re the people who designed the sand system for the NOVA documentary on Raising the Obelisk / Secrets of Lost Empires. I have to admit I wasn’t impressed by the documentary. I thought there was far too much faffing around and the experience of the workers seemed to be ignored. Luckily for me I saw the system in operation at the AIA conference in January and I was much more impressed. They had an excellent model which gave me much more confidence of the physics of how the system worked. Crucially, the people demonstrating were the people who designed the system and they did a much better job of it than the TV crew.
Their site also shows some of their other work including the Bushnell Turtle. It’s an excellent way to lose an afternoon when you should be working.