Jerry Pratt saw sky on the video monitor and knew he'd fouled up. The sky—southern California blue as usual on a June afternoon in Pomona, about 30 miles east of Los Angeles—wasn't the problem. The problem was that there was only one reason to see sky on a monitor connected to a camera connected to the head of a very expensive, very sophisticated humanoid robot. Instead of stepping nimbly onto a small pile of cinder blocks, the robot, nicknamed Running Man, had fallen flat on its back.