These 15 glyphs are listed for G under mama in my catalogue:

Ga1-16	Ga2-25	Ga2-29	Ga3-23	Ga4-23	Ga4-24	Ga7-3
Gb1-9	Gb1-11	Gb1-14	Gb1-19	Gb2-8	Gb2-10	Gb6-18	Gb8-16

There are two basic variants of mama, those with ovals which have marks inside their perimeters (black above) and those which have none such. The latter variant should not be confused with the tao glyphs:

tao	mama

On the other hand such mama glyphs as in Ga4-23--24 have the same type of outline as tao glyphs. I once decided, though, to keep 'tao' glyphs with internal markings separated from those without such marks and instead to have them at mama.

The summary at tao:

The tao glyphs are like 'hot buns' immediately after having come out from the 'oven'. They indicate the vitality of the very young. Gradually the force of vitality abates and they become cooler. At the end of their movements all their warmth will have gone away. They have become stiff as dry wood (toa): tao tapa mea toa The form of tao is like that of a canoe or an eye, both capable of very quick movements.

The system of rongorongo signs has several 'dimensions', but two of them obviously are significant for understanding mama glyphs:

	light	dark
elongated
rounded

The normal way of orientation for the 'chevrons' in mama glyphs is as in these two examples, and judging from the pattern on the plates of chitons it could mean 'head down'. And be another argument for chevrons signifying 'darkness' (as when you fall on your face).