I have the book Civilization One myself and so am familiar with the pendulum theory that the authors present for the MY. However the book completely ignores the evidence which researchers such as John Neal and John Michell have presented which implies the so called "English" foot is the root measure of an integrated system of metrology, a system which adequately explains many of the various ancient foot and cubit variations. The cubit used at Giza and the unit of measure found at Teotihuacan by Hugh Harleston fit perfectly into this scheme, as do the MY and known variants of Greek and Roman feet etc.
The foot on the equator equals 1000 x 365.22 for each degree, the number of feet in the circumference of the Moon equals 12 raised to the 7th power, the number of miles in the mean circumference of Earth equals 12 raised to the 5th power divided by 10. No other measure is at once so commensurate with nature and numerically amicable. There are some interesting links with the meter too, when we consider that precisely 3048 meters = 10,000 feet. There are 5280 feet in a mile and it turns out that 5280 meters = approximately 10,000 x √3 or 17322.8346456 feet. This because the ratio 5280:3048 or 220:127 is an approximation of the √3.
The equatorial radius of the Earth is 3963.19 miles, this squared equals 5 million x 3.1414, a very good approximation of pi. Civilization One links the pendulum to the motion of Venus. The equatorial radius of Venus in miles is 3760.41 miles and this squared equals 1.414 x 10 million, a very good approximation of the √2. Thus we see that time and again the foot and mile combine decimal notation with key mathematical and calendrical constants and ratios. For me the real mystery lies in the origin of the foot itself, as opposed to its variants.
There is a good overview of Michell's and Neal's metrology here:
As above, so below!