What self-propelled device did Leonardo da Vinci design for moving without an animal?

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

The cart used springs inside its mechanism to store energy, much like a modern clockwork toy. Cords and gears controlled its movement, and a steering system could make the cart follow a programmed path. Leonardo may have intended it for theatrical performances or court festivities, where a moving object could create an impressive stage effect.

The cart was not powered by steam, electricity, or an internal-combustion engine. Its operation depended on mechanical energy released from springs. That distinction matters because the device is sometimes loosely labeled the world’s first automobile, even though it carried no passengers and was not a road vehicle in the modern sense.

A reconstruction built for an exhibition in Florence in 2006 demonstrated that the design could work when interpreted as a clockwork mechanism.