1. I think this type of glyph indicates a period of six solar months.
2. It is shown by three double-months, similar to the method used in Pachamama's skirt. But instead of two concentric circles we have one circle divided in two for each such double-month.
3. The location in rows nos. 4 and 18 of two identical glyphs of this type is a kind of affirmation of these ideas. 18 - 4 = 14, i.e. half of the total 28 periods to cover 364 days. 14 * 13 = 182.
4. According to my almanacs 'winter' + 'spring' = 94 + 90 = 184 days (south of the equator).
Considering that period no. 4 covers days nos. 40 - 52, we can calculate: 40 + 184 = 224 and 52 + 184 = 236. As period no. 18 is defined (in my preliminary 'map') to contain days nos. 221-233, we get an idea of where in time these six-month period start and end.