What kind of machine did Leonardo da Vinci sketch to produce continuous motion from falling weights?

Leonardo da Vinci sketched a perpetual-motion machine intended to produce continuous motion from falling weights. His notebooks show wheels, overbalanced weights and mechanical arrangements designed to keep turning indefinitely.

Leonardo eventually recognized that such devices cannot work because friction, air resistance and energy losses prevent a machine from delivering endless motion without an external energy source. His studies are valuable evidence of a transition from imaginative mechanical speculation toward more realistic engineering analysis.

A perpetual-motion machine is not the same as a self-running clock or waterwheel. Those devices can operate for long periods only while consuming stored or supplied energy. Modern physics expresses the impossibility through the laws of thermodynamics: energy cannot be created from nothing, and every real process produces losses.