Fact is, in the studied texts the glyphs with henua concave at left are more freqent than henua concave at right:

Bent henua are equally frequent on both sides (a and b), and the sums give us no sign of a correlation between side and direction of 'concaveness'.

75 % are concave at left, which I take as a sign of a positive correlation between concave at left and summer.

Therefore there shouldn't be any correlation between summer and the side (a or b) of the texts. Which, though, does not imply that there may be such a correlation in a specific text, e.g. S - where side a has many bent henua (in the normal fashion), but where only a few are to be seen on side b.

From this (a correlation in S) follows, however, that another correlation (between normally bent henua on one hand and side b on the other) becomes discernible. On side a of S, it seems, summer is described, while on A summer may be found on side b. Yet, A is a special case - 15 of the glyphs in the text are involving ragi. These glyphs are distributed like this:

Now a positive correlation between side b and concave at right emerges. Still, summer seems to be located on side b of A, but on side a of S. Presumably we should rely on Metoro and start reading A on side b, and then summer will be located at the beginning of the text both in S and A.

If Metoro saw a sign of Tagaroa crying out alone in the darkness in what has been labelled the 4th season below, then it is tempting to imagine the Easter Island month Tagaroa uri to be involved in this 4th season:

1
	Eb3-9	Eb3-10
	e tagata aro ki te rima	tarai hia te vae o te vaka
2
	Eb3-11	Eb3-12
	te ragi	rima hakarava hia
3
	Eb3-13	Eb3-14
	kua tua te vaivai	rima
4
	Eb3-15	Eb3-16
	kua tuo te tino	te rima - te kihikihi
5
	Eb3-17	Eb3-18	Eb3-19
	kua moe - kua reva te ika	tama - reva ika	kiore - henua

But that step is not secure. Tagaroa uri is located at the beginning of summer in the Rapa nui calendar (at least we have been told so). And the assumed 3rd and 4th double-months incorporate what I have concluded are glyphs (Eb3-13 and Eb3-15) which mark the summer half.

Maybe the bent henua have been derived from straight henua and the shell halves in pure glyphs. The body of Tagaroa lost feathers which fell down and became trees. Tree stems are what straight henua probably depict.

The normally bent henua (not those incorporated in pure glyphs) would then mean the season of Tagaroa, while those bent henua which have their concave side at right would mean its opposite (winter).

This hypothesis can be tested in various ways. A first natural test is to read in Makemson about what month names there were in Polynesia. Maybe on Tahiti (where Metoro lived when he read the texts for Bishop Jaussen) the names of the months were different.