What defensive vehicle did Leonardo da Vinci sketch with sloped armor and multiple guns?

Leonardo da Vinci sketched an armored vehicle with sloped armor and multiple guns.

The vehicle is often called Leonardo’s fighting vehicle or Leonardo’s tank. His drawing shows a conical, tortoise-like cover made from angled wooden plates, with openings for cannons around the lower edge. A crew inside would turn cranks connected to wheels to move the machine.

The sloping armor was significant because angled surfaces can deflect incoming projectiles more effectively than flat vertical plates. The design was intended for battlefield intimidation and protection, although there is no evidence that Leonardo’s vehicle was built or used in war.

A famous modern interpretation points out that the crank arrangement in the surviving drawing appears mechanically inconsistent: some gears would make the wheels turn in opposite directions. This may have been an error, or possibly a deliberate flaw in a design Leonardo did not want fully built.