as not only a way to indicate that there are 4 weeks in a month (which we have seen is quite in agreement with the calendar in Mamari where there are 28 nights for the visible moon), but also a way to indicate that we need number 4 to complete the solar year from 360 to 364.

360 reflects - as we have seen on the previous page - 42 / 7 = 6 periods with 60 days. And in Small Santiago we find 28 * 13 = 364 days.

So 28 = 4 * 7 and 13 we find as the number of spines in the Monday creatures:

7 + 6 = 13 (quite similar to 7 * 6 = 42).