A recent paper from Tel Aviv regarding Egyptian standard sizes for round pottery jugs may have inadvertently helped to solve an Egyptian mathematical mystery:

http://www.sci-news.com/archaeology/article00367.html

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033895

A cursory examination of the new information suggests it is significant and may provide a long-sought-after explanation for the seeming existence of two different measurement traditions used for circular calculations in Egypt: one algorithmic, used in papyri and based on a diameter of 9 units (i.e. 28/9), and one geometric and used in monumental architecture and based on a circumference of 3+1/7th times the diameter (i.e. 22/7) (Legon 1990; Legon 1991; Lightbody 2008; Cooper 2011: 478; Lightbody 2012).