What vehicle did Leonardo da Vinci design with a conical gear system and no visible animal power?

Leonardo da Vinci designed a self-propelled cart powered by coiled springs and geared mechanisms.

The cart, usually dated to around 1478–1480, was conceived as a moving platform that could travel without horses pushing or pulling it. Two large springs stored energy, while a transmission system transferred that energy to the wheels. A steering mechanism also allowed a route to be set in advance.

The surviving drawing is not a complete modern-style blueprint, and scholars have debated how every part was intended to function. Nonetheless, reconstructions have demonstrated that the basic mechanism can move a cart using spring power.

It is sometimes described as an early automobile, but that label can mislead. Leonardo’s vehicle had no combustion engine and was designed for short, controlled movement. Its closest mechanical relatives are spring-driven automata and theatrical machines rather than modern cars.