From Karen
I just watched a film about the Eames' 901 studio and glimpsed a clever idea that we might want to try with marble machines.
Imagine a tower of xylophone parts that you could remove and rearrange to play tunes. Theirs was very tall and had an elaborate pneumatic launch, but I think it would be simpler and cooler for our purposes to have the marbles fall into the "tower" from things that visitors construct with tracks.
http://blog.makezine.com/archive/2009/10/the_gravity-powered_xylophones_of_c.htmlFrom Jessica
That sounds interesting! Your description reminds me of a very cool toy I saw once: