What type of vehicle did Leonardo da Vinci design with two large rear wheels and a spring-powered mechanism?

Leonardo da Vinci designed a self-propelled cart with two large rear wheels and a spring-powered mechanism.

The drawing appears in the Codex Atlanticus, a major collection of Leonardo’s notes and sketches. The cart used coiled springs to store energy, while gearing transferred that energy to the wheels. Its steering system could be set in advance, so the vehicle was intended to follow a predetermined route rather than respond continuously to a driver.

Modern reconstructions have shown that the design can move under its own stored power. For that reason, it is often described as an early ancestor of the automobile or robot. It was not an engine-powered car: Leonardo’s machine depended on mechanical springs, not petrol, steam, or electricity. The design also should not be confused with Leonardo’s armored vehicle, which was a separate military concept.