waxing full moon waning
period 1 8 period 4 8 period 6 7
period 2 11 full moon period 7 11
period 3 9 period 5 10 period 8 8
sum 28 sun 18 sum 26
illuminated 20 56 nights with illuminated moon illuminated 18
no moon visible 8 no moon visible 8

The Mamari moon calendar is structured with the 1st period separated from the following two. Not only the shapes of the night glyphs (showing moon crescents) indicate the difference between the 1st period and the rest, but also the number of glyphs.

28 - 8 = 20 glyphs for the waxing moon is followed by 18 for full moon and another 18 for waning moon. Period 8 is exceptional and balances period 1 with another 8 glyphs.

The number of glyphs (20 + 18 + 18 = 56) is coordinated with the number of nights in a lunar double-month. 29½ * 2 = 59 and 3 of them are dark. During 56 nights the moon can be visible (weather allowing).

The number of periods is 1 + 6 + 1 = 8. Twice the calendar must cycle during a lunar double-month, i.e. 2 * 6 = 12 (maybe alluding to 6 months before midsummer and 6 after) and 2 * (1 + 1) = 4 (perhaps alluding to the 4 corners of the earth).