Another perfect visualisation method

http://www.sentex.net/~mwandel/marbles/machine1.html

check out the video.

I like the image that every time someone walked up the stairs you get this ball running down a track all the way from the 2nd floor to the bottom. If you take the lift you get another ball to another bin. Perhaps you would get a physical balance at the bottom just to reinforce the point.

I could see a really big tube/sculpture (?) hanging suspended from wires in a spiral in the atrium - make a really big statement grab lots of attention. The noise would be attractive to.