Writing Matrix of Creation as the 21st Century began, I was initially struck by the exactitude of eight practical years of 365 days equalling five synods of Venus (583.92 days), accurate to within two hours. One can see the factors of 365 are 5 times 73 days so that 8 times 73 days equals 584 days, indicating that the practical year of 365 solar days is synodically related to Venus with a common unit of 73 days. The number of lunar months in 365 days then proved to be 12.36 and 0.36 is 9/25. and 12.36 = 309/25.

This formula. 309/ 25 leads back to the Egyptian calendar where it was noted that 309 lunar months is (to within 68 minutes) the same length of time as 25 years in their civil calendar of 365 days. That is, the Egyptians exploited an anniversary of 25 practical years and 309 lunar months. We know that 5 and 8 are members of the Fibonacci series (1,1,2,3,5,8,13,...) in which adjacent members (which 5 and 8 are) form approximations to Phi the Golden Mean. The number 309 also points to the Golden Mean of 1.618034 since the fractional part (618) is 309 x 2. 

"the number 309 is half of 618 (0.618 x 1000) and forms an excellent approximation to 0.618034. But five hundred [half 1000] divided by 25 is twenty. Therefore, there are twenty times 0.618 lunations in a practical year (20 x 18.25 days = 365 days) ... Thus a new unit has emerged that is 0.618 of the average lunar month  (29.53 days)." page 39

Since the practical year already contains 5 of the 73 day units shared with the Venus synod of 8 such units, then dividing 73 by a further 4 gives one 20th of 365 days as 18.25 days. Interestingly, in 0.618 lunar months there are 0.6678 lunar orbits (that is, two thirds of an orbit) and so synchronicity of the most literal kind appears to be operating between the Moon, the solar days in a year and in the Venus synodic period.

additionally: The sidereal period of Venus (i.e. its orbital period) is 224.701 which is 8/13 of a solar year (i.e. Earth's orbital period), and 8 and 13 are the next pair of numbers in the Fibonacci series. This eventually points to the fact that the movement of the sun every day (due to the earth's orbit) divides into the lunar orbit 10,000 times, making that nearly 4 minute lengthening of the solar day over the sidereal day, a common factor of both the solar day and the lunar orbital period - a period I named the Chronon, after the god of time. 

By the end of Matrix of Creation, it becomes obvious that the practical year has some relationship with harmony since the Babylonian year of 360 days (shared also by the Egyptians) relates to the practical year as 365/360 = 73/72 = 1.0138 whilst the Pythagorean comma (the dissonance between seven octaves (2/1) and twelve fifths (3/2)) equals 1.01346 = 74/73, which is similar to the geographical constant of the Earth's shape in which a degree of latitude for the mean earth (and at Stonehenge) is 360,000 feet of 1.01376 feet whilst a day (1/365.2422th) in longitude at the Equator is 360,000 feet. [Matrix of Creation, 2nd edition, page 129-132].