Attempting to increase the fire power of a traditional cannon, Leonardo da Vinci designed this innovative 12-barreled gun carriage. Though hardly capable of rapid-fire, this design housed an ingenious aiming and loading mechanism. The fan-like shape made it a potentially effective weapon against massed advancing troops, by widening the field of fire and reducing possible mistakes. Additionally, its lightweight and large wheels would have provided for excellent mobility on the battlefield.
The aim of the tiers is that in rotation, the first tier is fired while the second tier can be loaded. This allows for the third tier to cool down before its turn in the rotation to be loaded and fired again.
Leonardo always aimed to increase the firepower of the weapons he worked on and to maximize their overall destructive capacity. He did this for both his Patron's benefit in having superior firepower compared to his rivals and for his own personal, intellectual curiosity.