The Great Pyramid is 756 feet long on each side, 450 high and is composed of 2,300,000 blocks of stone, each averaging 2 1/2 tons in weight.

If you wanted to make it realistic, you would not be able to use just any old random function to emulate its shape. So you would be looking at a rather complex bump map. Of course, there is the easy way out . . . make it as it appeared when it was new. . .