What did Leonardo da Vinci’s armored vehicle design use to move its wheels?

Leonardo da Vinci’s armored vehicle design used cranks operated by men to turn its wheels.

Created around 1487, the machine was a conical, armored wagon with sloping protective panels. Inside, several men would turn cranks connected to the wheels, allowing the vehicle to move across the battlefield while shielding its crew from attack.

The vehicle is often called Leonardo’s tank, but it was not a modern tank. It had no engine, turret or tracked suspension, and its weapons were arranged around the outside. A commonly discussed drawing also appears to contain a gear arrangement that would prevent the machine from moving as shown, perhaps deliberately or because of a design error.

Leonardo may have proposed the machine as a military device or as an impressive concept for a patron. No evidence shows that it was built in Renaissance Italy.