Moon and Mars are upholding the sky roof in spring and Mercury and Jupiter in autumn. The peculiar Moon glyph could represent the beginning of the first quarter of the year and it looks like a great tree, a cosmic pillar.

A tree is casting shadows below, and the bottom part of gagana at right in *Ka1-21 seems to be alluding to the great tree.

With the Moon pillar at *Ka1-20 and also in crescent form in *Ka1-21 and *Ka1-22 the subject appears to be the phases of the moon:

The gagana bird at right in *Ka1-21 is positioned where we expect to find the black new moon, with a waning crescent at left and a waxing at right.