"[T]here is one theory that is never taught by Egyptology, but which is obvious. I call it Theorem Number One. The stone has a religious meaning. Stone is used only for tombs, pyramids and temples. Stone is never used for secular constructions, never for palaces, garrison, houses that are made out of wood, clay, brick, never in stone, except during the Greek period... and during the Roman occupation. So never, during the genuine Egyptian civilization, was the use of stone permitted for secular constructions."