What armored military vehicle did Leonardo da Vinci design with cannon arranged around its body?

Leonardo da Vinci designed a fighting vehicle, an armored military machine with cannon arranged around its body.

The vehicle was drawn as a conical, turtle-shaped cover mounted on wheels. Its sloping armor was intended to deflect enemy fire, while several light cannons projected through openings around the perimeter. Inside, men would turn cranks connected to the wheels to move the vehicle.

Leonardo prepared the design during the 1480s, when he was seeking employment from Ludovico Sforza, the ruler of Milan. He presented himself as an engineer able to design fortifications and weapons as well as works of art. The vehicle was never produced as a practical battlefield machine.

Modern illustrations sometimes call it a tank, but that label is retrospective. Leonardo’s design had no engine, enclosed crew compartment in the modern sense, or demonstrated military use. It remains one of his best-known military inventions.