Leonardo da Vinci sketched an armored tank with sloped armor and eight wheels.
His fighting-vehicle design appears in drawings from around 1487–1490. The machine resembles a conical, turtle-like cover made from wooden plates strengthened with metal. Sloping the armor would help deflect projectiles, while a ring of small cannons around the platform would allow firing in several directions. Leonardo imagined a crew operating the vehicle from inside.
The vehicle is frequently called Leonardo's tank, but it was not a modern tank and was never built for battlefield use in his lifetime. Reconstructions usually identify a flaw in the surviving design: the internal cranks, as drawn, would make the wheels turn in opposite directions. Some historians think this may have been an intentional error to prevent others from using the design, while others treat it as a mechanical mistake. The project shows Leonardo combining fortification, artillery, and transport ideas rather than inventing the fully developed armored tank of the twentieth century.