I opened the course to 50 undergraduates from all different departments of the university. We had actors, English majors and sculptors mixed with engineers, math majors and computer geeks. These were students whose paths might never have had reason to cross, given how autonomous the various disciplines at Carnegie Mellon could be. But we made these kids unlikely partners with each other, forcing them to do together what they couldn't do alone. There were four people per team, randomly chosen, and they remained together for projects that lasted two weeks. I'd just tell them: "Build a virtual world." And so they'd program something, dream up something, show everyone else, and then I'd reshuffle the teams, and they'd get three new playmates and start again. I had just two rules for their virtual reality worlds: No shooting violence and no pornography. I issued that decree mostly because those things have been done in computer games only about a zillion times, and I was looking for original thinking.