What wheeled device did Leonardo da Vinci design with a programmable mechanism for producing patterns?

Leonardo da Vinci’s wheeled programmable device is known as the self-propelled cart.

Leonardo designed the cart around 1478, making it one of his earliest known mechanical inventions. Springs wound inside its drum-like body supplied power, while a system of gears controlled the wheels. Adjustable blocks on the mechanism could determine the cart’s route, allowing it to follow a programmed path and create repeated movements.

The cart was probably intended for theatrical or ceremonial use rather than transportation. It may have been able to move automatically across a stage or carry scenery during court performances. Unlike a modern automobile, it had no engine, steering wheel, or practical passenger compartment.

A reconstruction made in the early 21st century demonstrated that the design could operate when built from Leonardo’s drawings. The device is therefore often described as an early robot or programmable machine, although those modern labels should not imply that Leonardo built a general-purpose computer or autonomous vehicle.