A ball is free to rotate on a hinge, 2 or 4 L-shaped nozzles stick out of the ball, the ball is to be filled with water, and a source of heat (such as fire) is placed underneath the ball, as the water gets hot, it turns to steam that forces its way out of the nozzles, pushing the ball around, therefore, the aeolipile is a kind of reaction turbine, and the nozzles use a similar principle to rockets.