Leonardo Da Vinci worked as a military engineer before he became a painter IIRC. Now he designed some very unique weapons. But what caught my eye the most was his 3 barreled and later 8 barreled cannons, and his cannon that could adjust elevation. So its the 15th century how could these inventions become widespread? What affect could it have? An 8 barreled cannon could have a machinegun like effect, however they would be buggers to reload. What would the world be like if Da Vinci's military inventions gained prominence?