What type of vehicle did Leonardo da Vinci sketch as a self-propelled cart?

Leonardo da Vinci sketched a spring-powered cart as a self-propelled vehicle for ceremonial use.

The cart appears in Leonardo’s late-15th-century drawings and used coiled springs to store mechanical energy. Gears transferred that energy to the wheels, allowing the vehicle to move without an animal pulling it. The design may have been intended for theatrical or court entertainments rather than ordinary transportation.

It is often described as an early automobile, but that label can mislead. Leonardo’s cart did not use an internal-combustion engine, electricity, or steam. Modern reconstructions have shown that the mechanism can work when built according to the surviving design, although details remain uncertain because Leonardo’s notes are incomplete. The cart is therefore best identified by its power source: springs.