"Just after, what we have is the starting of making a small pyramid in carved stone. ...We have here the pyramid of Ouserkaf (2460 B.C.)... just after the pyramid of Giza. It is just a heap of small stones... this one is totally destroyed and ...[the (2650 B.C.)] is still there. ...[T]his is big difference between a building made out of agglomerated stone and a small building made out of carved stone. ...It is no longer this very powerful and important technology..."