Which Leonardo da Vinci design used a wheeled platform and coiled springs to move without an animal?

Leonardo da Vinci designed a self-propelled cart powered by coiled springs rather than an animal.

The cart appears in drawings from the late 15th century and is often described as an early programmable machine. Two large springs inside drums supplied the driving force, while steering could be set through a system of pegs and shaped guides.

The design may have been intended for theatrical performances or court celebrations. A moving device that could travel on its own would have created a striking effect for spectators, without requiring a visible driver.

It is sometimes called Leonardo’s automobile, but that label can mislead. The cart was not powered by an engine, and its documented purpose is uncertain. Modern reconstructions have shown that the mechanism can move when built according to Leonardo’s surviving drawings, although details of the original design remain open to interpretation.