What rotating weapon did Leonardo da Vinci design with several barrels arranged in parallel?

Leonardo da Vinci designed a 33-barrel organ, a multi-barrel firearm intended to fire several shots in sequence or together.

The weapon consisted of three rows of eleven small guns mounted on a wheeled frame. The arrangement allowed one row to be fired while another could be loaded, offering a faster cycle than a single muzzle-loading gun. Its fan-like layout also gave the weapon a broad field of fire.

The name organ refers to the grouped barrels and their visual resemblance to the pipes of a musical organ. It was not a machine gun in the modern sense: the barrels did not fire continuously through a powered automatic mechanism. The design still illustrates Leonardo's interest in improving battlefield firepower through repetition and organization.

The 33-barrel organ was a proposal, not a weapon known to have entered regular service. Renaissance artillery was limited by slow loading, inconsistent gunpowder, recoil, and the difficulty of moving heavy equipment. Leonardo's design addressed some of those problems but introduced others.