simulated

Not sure if it was here or on the old interweb but I once came across a website that simulated motion. You could change stuff around like pulleys and bars and it would show the results. Any ideas? Thanks

Ive only seen two videos, but the effect is amazing, something with a fog machine, some form of pipe, and lighting, but some questions that spark in my mind are- what color lights,? how many? is the pipe perforated or do you have to?if so... is it holes or thin slices, do you need fans. It looks...