What weapon did Leonardo da Vinci sketch with 33 barrels arranged in parallel rows?

Leonardo da Vinci sketched a 33-barrel organ, a multi-barrel weapon arranged in parallel rows.

The design placed small cannon-like barrels on a broad frame. Its nickname comes from the resemblance of the aligned barrels to the pipes of a musical organ, not from any musical function. The arrangement was intended to let several shots be fired in succession or in a concentrated volley, depending on the operating method.

Leonardo’s military notebooks contain many proposals for improving artillery mobility, rate of fire, and battlefield impact. The 33-barrel organ belongs to that wider group of experimental weapons. It was a paper design rather than a documented battlefield weapon successfully built and deployed by Leonardo.

The device is sometimes called a multiple-barrel gun or organ gun. It should not be confused with the modern machine gun, which uses a different loading and firing system and developed much later.