Leonardo da Vinci designed a self-propelled cart powered by wound springs and mechanical gearing.
Leonardo sketched the cart in the late 15th century, probably as a theatrical machine rather than as a road vehicle. Two large leaf springs stored energy, and a system of gears transferred that energy to the wheels. A steering system allowed the cart to follow a preset route.
The cart is sometimes described as an early automobile because it could move without an animal pushing or pulling it. That comparison is useful, but it should not imply that Leonardo had an internal-combustion engine. The machine relied on stored mechanical energy and could travel only a limited distance.
The original drawing does not survive as a complete standalone sheet, but the design is known from Codex Atlanticus material. Modern builders have created working reconstructions, including a 2006 model displayed at the Clos Lucé in France. Its likely purpose was to create programmed movement during court performances.