What mechanical device did Leonardo da Vinci sketch to produce continuous motion from a weight?

Leonardo da Vinci sketched a perpetual-motion machine to explore whether a weight could produce continuous motion.

Leonardo drew several mechanisms involving wheels, weights, gears, and levers. Their arrangements attempted to keep one side of a wheel heavier than the other, creating uninterrupted rotation. These sketches reflect his careful investigation of mechanics and his interest in testing claims about machines that might run indefinitely.

Leonardo ultimately recognized that such designs could not provide endless useful motion. Friction, air resistance, deformation, and the conservation of energy prevent a closed machine from producing more energy than it receives. His notebooks therefore show an important shift from imaginative mechanism design toward critical mechanical reasoning.

A perpetual-motion machine is not an operating invention that supplies free power. Leonardo’s sketches are valuable because they document an investigation into an impossible goal. They also differ from practical machines such as clocks, water wheels, and engines, all of which require an energy source and lose energy through friction.