Leonardo da Vinci sketched an armored tank as a covered, conical vehicle driven by cranks and intended for battlefield use.
The machine appears in Leonardo’s work from the late fifteenth century. Its sloping shell was designed to deflect projectiles, and the vehicle was shown with openings for weapons. Several crew members inside would turn cranks connected to the wheels.
The drawing is often called Leonardo’s tank, although it was not a modern tank and was never built as an operational Renaissance weapon. The design depended on human power and had practical problems, including the weight of its armor and the difficulty of moving it over uneven ground.
A famous claim says Leonardo deliberately inserted a flaw so an employer could not use the design against him. That story is uncertain. The reversed gears visible in some interpretations may instead reflect drawing conventions, copying, or an unresolved design problem.