The young Leonardo was fascinated by the drawings of recirculation mills that he discovered in manuscripts by other engineers, and he studied the subject thoroughly. He imagined basins that would be filled with water by automatic means. Eventually, he imagined full-fledged hydraulic power plants composed of several wheels powered by the millpond fed by the basin into which the water would be conveyed by Archimedes’ screws or pumps driven by the motors themselves. Leonardo seems to have realized the difficulty of achieving perpetual motion, for he increased the complexity of these machines in an attempt to find the solution that would keep the entire system in motion.