What repeating firearm did Leonardo da Vinci sketch with multiple rows of barrels?

Leonardo da Vinci sketched a 33-barrel organ, a repeating firearm arranged in multiple rows.

The machine was a type of organ gun, meaning that several small cannon barrels were mounted together. Leonardo’s arrangement placed the barrels in three rows of eleven. The idea was to fire a volley, then allow another row to be prepared while the weapon was repositioned or reloaded.

The nickname “organ” came from the visual resemblance between the parallel barrels and the pipes of a musical organ. Leonardo’s concept was intended to improve the rate of fire of a gun battery, not to create a handheld firearm. Its practical effectiveness would have depended on construction, ammunition, and a reliable firing system.

The design belongs to Leonardo’s military notebooks and is not evidence that he invented the modern machine gun. It was a volley weapon using multiple barrels, whereas modern machine guns fire ammunition continuously or in rapid succession through a repeating mechanism.