sentences:  The inside of the machine was divided into nine separate stories, each accessible through a long flight of stairs that wound from the ground floor to the very top.Over 3,600 men were needed as crew, working in relays to drive the helepolis, which weighed over 160 tons.In addition to being strongly defended, the helepolis was powerfully armed; several catapults and balistas were placed on each of the floors, each outlooking the battlefield through large shutters.