The full moon (Omotohi, 'End-of-sucking') glyph is expressing the concept of break in time -  here between waxing and waning moon - by using a broken 'stick' (the sign inside at bottom of the oval):
Ca7-24
Omo

To suck; omoaga, bulky cloud;  ragi omoaga cumulus; omoomo; to suck repeatedly, to suckle; omotahi, to win everything at a game (lit: to suck whole): omotahi-mai-á e au, he has cleaned me out; omotohi, full (of the moon); ku-omotohiá te mahina, the moon is full. Vanaga.

Rima omo, infidelity, faithless, unfaithful. Omoomo, to smack the lips, to suck the breast, to smoke tobacco, to taste of; hakaomoomo, to suckle, to paint. Churchill.

Ta.: Omotu, an ember, a coal. Mq.: komotu, omotu, firebrand. Churchill.

Tohi

Omotohi, full (of the moon); ku-omotohiá te mahina, the moon is full. Vanaga.

Mgv.: tohi, to cut breadfruit paste. Ta.: tohi, a chisel, to cut, to split. Mq.: tohi, to cut up. Sa.: tofi, a chisel, to split. Ma.: tohi, to cut, to slice. Churchill.

Ha.: kōhi. 1. To gather, as fruit; to break off neatly, as taro corm from the stalk with a stick or knife; to split, as breadfruit; to dig; splitter, as stick, stone, knife. Nā wāhine kōhi noni, the noni-gathering women (an insult to Pele, perhaps likening her disposition to sour noni fruit). (PPN tofi.) 2. Fat, rich, as food; fatness. Nā kōhi kelekele o Kapu'u-kolu, the rich foods of Ka-pu'u-kolu (Kaua'i, famous for abundance). 3. To fill or heal, of a wound. Ke kōhi maila ka 'i'o, the flesh is beginning to heal. 4. To hold back, check, restrain: to strain, especially as in childbirth, to travail; to hold or hold back by pressing a person's arm, as in withholding consent, or as in urging someone not to be generous; labor pains, travail. Fig., agony, fear. Cf. haukōhi, kāohi, ho'o kōhi. Also ha'akōhi. 5. Prolonged, as a sound; long. He kōhi ka leo, the sound is long. Wehewehe.

A baby sucking (omo) will grow. Growth will stop if the connection is cut off (tohi). The little person inside the oval possibly is drawn with thumb in mouth.