" The engineering context of precision where precision is not necessary indicates the existence of sophisticated tools. These have not been found in the archaeological record, but the existence of them must be taken into account when we consider the mountain of circumstantial evidence to support their use.
In the case of the Serapeum, the list of tools and instruments that are necessary to create the granite boxes has grown. We can say with certainty that exact measuring instruments existed, for this work and the work at Luxor and Karnak could not have been accomplished without them. They are the most important and necessary tools for such work. The wooden squares, plumb bobs, and alignment instruments on display in the Luxor and Cairo Museums are incapable of giving even the most talented craftsman the information he needs to know that his work has achieved this kind of accuracy. Even if these boxes and monuments were crafted today with modern tools, such instruments are limited in what they can measure--and they most certainly cannot explain the precision and geometry [on display]. "

― Christopher Dunn , Lost Technologies of Ancient Egypt: Advanced Engineering in the Temples of the Pharaohs