The tank that Leonardo invented was equipped with 360 degree cannons all around it for maximum damage. Its outer shell was designed based off of a turtle's shell, as da Vinci liked to take his designs from nature. His intention was to create a vehicle able to drive straight onto a battlefield that was inpenetrable but also provided damage to the enemy. Nothing even close to his invention would be seen until world war I, proving that Leonardo certainly had a mind ahead of his time.