 They didn't have a metal hard enough. They only had either copper in the beginning or later bronze, which is much softer than granite. So they couldn't get them out that way. What they did was they took another hard stone called dolerite, and they pounded these obelisks out. They were pounded out by probably prisoners, dropping this dolerite ball that weighs about 16 pounds. It looks a little bit like a small, dense bowling ball. And they would line up along this line drawn by the Overseer of the Works and start pounding out this obelisk from the quarry.