What did Leonardo da Vinci’s early armored vehicle use to move across the ground?

Leonardo da Vinci’s early armored vehicle used cranked wheels to move across the ground.

The vehicle was a conical armored fighting machine covered by wooden panels reinforced with metal. Inside, crews would turn cranks connected to the wheels, theoretically driving the vehicle forward while protecting the operators from enemy fire.

Leonardo’s drawing contains a famous mechanical problem: the crank and wheel arrangements appear to oppose one another, which would prevent the vehicle from moving as drawn. Some historians have suggested the flaw may have been deliberate, preserving a technical secret or disguising the design.

The vehicle is often called a tank because of its armored shape, but it was not a modern tank. It had no engine, tracks, turret, or reliable evidence of construction and battlefield use.