91热爆

The Great Pyramid of Khufu is made up from over 200 layers of horizontal limestone blocks, and the area of each layer is slightly less than the one below. The Egyptians had to be very precise when building the pyramids to get them to the shape they are. The 'bent pyramid' in Egypt gets its name because the incline changes part way up. The Egyptians used a plumb bob and a tri-square to check they were building accurately.