My studies of the Ancient Near East in the light of the Göbekli Tepe led me to the dingir calendar of Sumer and Akkad and Babylon, a ceremonial or liturgical calendar of these numbers:
A long month had 45 days, a year 8 long months or 360 days, plus 5 days, 3 days of midsummer and 2 days of midwinter, New Year following midwinter. One year of 365 days was a short dingir cycle. Eight years of 365 days each were a long dingir cycle, 2920 days, followed by 2 more days, so a long dingir cycle had, all in all, 2292 days.
One year, short dingir cycle:
45 45 45 45 3 45 45 45 45 2 days or 365 days
Eight years, long dingir cycle:
365 365 365 365 365 365 365 365 2 days or 2922 days
Now the long dingir cycle combined 8 solar years and 99 lunar years or lunations or synodic months and 5 Venus years:
2921.9376 days --- 8 solar years
2923.5283 days --- 99 lunar years
2921 days --- 5 Venus years
2922.1553 days --- average
2922 days --- rounded average, long dingir cycle
The very ancient way of counting lunations or lunar years or synodic months (29 days 12 hours 44 minutes 2.9 seconds, modern average value from 1989 AD) was to lay out lines or rows of alternately 30 and 29 pebbles.
30 29 30 29 30 29 30 29 30 29 30 ... days or nights for 1 2 3 4 5 6 7 8 9 10 11 ... lunations
15 lunations counted this way yield 443 days or nights, and 17 lunations 502 days or nights:
15 lunations 443 days or nights 17 lunations 502 days or nights 32 lunations 985 days or nights
945 days or nights correspond to 32 lunations, mistake less than one minute per lunation, or half a day in a lifetime. 945 days are 21 times 45 days, the long month of the dingir calendar.
Now the dingir cycle was symbolized by a rosette of eight petals and a small circle in the center, each petal a month of 45 days, and the central circle 5 more days, together 365 days or a year, and the same rosette of eight petals symbolized the long dingir cycle of 8 years, each petal a year and the small circle in the center 2 more days at the end of the long dingir cycle. Midwinter was symbolized by a pair of opposing goats, while a goat nibbling at a petal visualized the passing of time ... There are numerous variants of visualizations; the long dingir cycle could also be represented as a tree of life of eight rosettes, or as two and two branches bearing four rosettes each, held together by the sky god Anu or An. On cuneiform tablets and cylinder seals, the dingir sign became a star of eight points in Sumer, in Akkad abbreviated to a cross with an additional wedge indicating a second cross under the first one, turned by 45 degrees. The dingir sign indicated a deity, and the phonetical value was an for sky.