The last major engineering task was the positioning of the capstone, basically a small pyramid, on the very top of the Pyramid. The pyramidion, as it is called, was made of fine limestone and probably covered with electrum, an alloy of gold and silver, and might have weighed as much as fifteen tons.48 We don’t know the details of how it was raised, but it certainly would have required advance planning because it is too large to be moved through the cramped internal ramp. After weeks on the computer, Jean-Pierre figured out a possible
scenario for the capstone’s movements. During the fourteenth year of Khufu’s reign, the pyramidion and
the beams and rafters for the King’s Chamber were pulled up the exterior ramp to the top of the Pyramid, which was now 150 feet high.
For the next five years the capstone moved upward, course by course, as the Pyramid was being built. It could have been suspended in a wooden pyramid-shaped cradle. The ropes holding the capstone could
be twisted, much the same way children twist the chains supporting swings. As the ropes twisted, they shortened, and the capstone was raised a bit. Wedges were slid under the capstone, and using wedges,
the cradle was raised the same height.