This is one of the two glyphs of this type in Keiti (the other is in period no. 12) where the sitting person has no feet. Why are they located in these periods, 7 and 12?

Among other things I imagine that a gap may stand for the transition from one 'rule' to another, a time when everything is out of order and we are holding our breaths to see what will come. When the clock strikes 12 in the midnight the ghosts are intruding.

Is there another, similar, transition at 7? I have looked anew at all the 20 glyphs of this type in Keiti and tried to sort them according to how the heads are carved. The numbers, I think, are not only 7 and 12 but also 9, 17 and 24. And 15 of the 24 glyphs have unmarked sitting persons, 9 have signs on them.

In the London Tablet I have also found this type without feet:

Ka4-3 Ka4-12 Kb1-1 Kb1-104 Kb3-8

I have marked it with red. The other four glyphs I have included for the sake of comparison, they are special too. Let us compare the glyphs in the period where Kb1-104 is located with those in the two periods nos. 7 and 12 in Keiti.