What armored vehicle did Leonardo da Vinci design in 1487 with conical covering and cannons?

Leonardo da Vinci designed an armored fighting vehicle in 1487, often called Leonardo's fighting vehicle.

The concept resembles a modern tank: a broad, conical wooden cover would protect men inside, while light cannons around the platform could fire in several directions. Cranks and gears were intended to turn wheels and move the vehicle across the ground.

Leonardo included the design in studies prepared while seeking work from Ludovico Sforza, the ruler of Milan. The vehicle was never built as a working military machine in his lifetime. Its famous design problem is that some gear arrangements would make the wheels turn in opposite directions, so the vehicle could not move as drawn without modification.

It is sometimes called a tank, but that modern term is retrospective. Leonardo's machine had no engine, turret, or tracked drive. Its importance lies in the combination of armor, wheeled movement, and multiple guns in one vehicle concept.