There are still some things that bother me about the Royal Cubit, in particular, why did they choose π/6, and why did they use it in preference to the metre.
Something interesting related to the first question has surfaced. Which may just be another random co-incidence like all the others, or maybe not.
First up, a reminder that the Royal Cubit is ⅙ of the circumference of a circle with diameter 1 metre, in other words the arc on a 360/6 = 60° segment, as follows:
As you may know, the ancient Egyptians were very fond of their ankh, which looks like this: