Okay, you’ve convinced me. The holes in the previous example were made using a copper tube and sand. I’m totally convinced. Ancient Egyptians could easily buy the necessary copper tube at any ancient hardware store. But there’s just one little problem here: this piece of granite. Now it’s time to put those engineering brains to work again and explain how this depression was made. We’ve already dealt with the hole. They cleverly drilled it using a copper tube and sand. Check. But now comes the hard part, boys! How did they make this depression? CAST!