What carriage did Leonardo da Vinci design to move itself using a wound spring mechanism?

Leonardo da Vinci designed a self-propelled cart powered by wound springs.

The drawing shows a three-wheeled vehicle with two large driving wheels and a smaller steering wheel. Coiled springs inside the cart would store energy when wound, then release it through gears to turn the wheels. The arrangement resembles a mechanical stage device or ceremonial vehicle more than a practical road car.

Leonardo’s sketch includes a programmable steering feature: pegs placed in a drum could determine the cart’s path. This makes the design notable not only for stored mechanical power but also for early ideas about automatic movement. Because the drawing is incomplete in places, modern reconstructions must infer how some components fitted together.

The cart is not powered by steam, fuel, or an animal. It is also different from Leonardo’s humanoid mechanical design, which is often called a robot. The cart’s purpose may have been theatrical or courtly, but its mechanisms anticipated principles used in later clockwork vehicles.