What did Leonardo da Vinci’s proposed armored vehicle resemble in plan?

Leonardo da Vinci’s proposed armored vehicle resembled a conical shell in plan.

The machine, usually called Leonardo’s fighting vehicle, was drawn as a covered platform with sloping armor and numerous cannon openings. Its circular, conical form was intended to deflect attacks while allowing weapons to fire in several directions.

Leonardo designed the vehicle around 1487–1490, during his service to Ludovico Sforza in Milan. The concept included wheels and internal mechanisms for movement, but the surviving design contains an important practical problem: the gearing as commonly drawn would make the wheels turn in conflicting directions. Some historians think this may have been deliberate concealment or simply an unresolved design flaw.

It is often described as an ancient tank, but it was not a functioning tank and was never used in battle. The modern label helps explain its purpose, while the original drawing shows a Renaissance siege-machine concept rather than a proven armored vehicle.