6	5	5	5	5	5
5	5	5	6	6	6
6	6	4	6	5	5
5	5	4	5	5	4
4	5	5	4	5	4
	6 * 4 + 18 * 5 + 7 * 6 = 24 + 90 + 42 = 156 'feathers'
5

Probably these 156 'feather' signs are at least partly drawn in order to secure a correct reading of the G text. 521 (= 260 + 261) minus 156 = 365, a message that the year is the subject of the text (securing a correct reading by 56 being the reverse of 65).

It may also be a hint that the 261 glyphs in the dark area form a complete calendar. Or, alternatively, that glyphs which do not belong in the 31-period long calendar together form another complete calendar. All the 156 'feathers' are in the light area (between Ga1-26 and Gb1-6).

521 + 156 = 677 = 13 * 52 + 1 is a fact which alludes to 13 * 28 + 1 = 365 (because there are 52 weeks in a year).

The distribution of the 'feathers' certainly is not arbítrary.