If you know of a machine that embodies, requires, enables, models, or demonstrates cooperation, let us know: howard at rheingold dot com

This machine was built by a group in Seattle and exhibited at Burning Man 2005. It's just called "the machine," but I call it "the cooperation contraption." Note the construction: it is built of inexpensive but strong materials, held together with hinges and guywires. It folds up to be transported in a truck, although it was transported only one way. The top platform, where the people are, rotates -- but only if volunteers keep all three of the lower turnstiles moving simultaneously. So you show up, see what's happening, get the story, and jump in and do your time on the turnstile and/or climb to the top and ride around. The night before the Man burned, people were invited to cooperate in destroying it -- many people had to pull on many ropes for quite a while to get it to collapse in on itself.