What mechanism did Leonardo da Vinci use to make his self-propelled cart move?

Leonardo da Vinci’s self-propelled cart used clockwork springs as its driving mechanism.

The cart was designed around 1500 and is often described as an early programmable machine. Two symmetrical leaf springs stored energy, while a system of gears transferred that energy to the wheels. Adjustable blocks inside the mechanism could determine the cart’s route, allowing it to turn according to a preset pattern.

The vehicle may have been intended for theatrical performances or court entertainment rather than transport. Leonardo’s original machine has not survived, so modern reconstructions rely on his drawings and related notes. In 2006, a replica was built and demonstrated at the Museo Galileo in Florence. The cart is sometimes called a robot, but it had no electronic control; its movement came entirely from mechanical power and prearranged settings.