The left of the two, not exactly identical but certainly similar creatures, has a black eye. Not so the right. The eye which is black is the New Moon, whereas the eye that is white is the Full Moon.
1. The left of the two creatures has a lean body in contrast to the one at the right. Here I suspect that the time of New Moon (placed with the left of the two creatures) would 'paint' that one as 'black' and lean, whereas the right one, for contrast, should be 'white' and fat.
2. In Polynesian thought the head is often compared to a nut. You plant the nut and up comes a plant. You can also put a head into the ground and expect something soon to be growing. The Waxing Moon, therefore, grows from the period of the New Moon, dark as if below the surface of the earth. The Waning Moon - if we continue with this reasoning - consequently must grow from the Full Moon.
3. Counting the 'spines' of the Waxing Moon and those of the Waning Moon, we can see that the Waxing Moon has 7 and the Waning Moon 6 only. Here, I suspect, another 'picture' of the New Moon is shown. 7 periods of light nights (= moon visible) preceed the Full Moon, 6 periods only are to be found from Full Moon to New Moon (= moon invisible). I.e. in this 'picture' New Moon is situated at the end of the Waning Moon, and the Waxing Moon starts when you can see a tiny sickle. Therefore the Waxing Moon has more light time than the Waning Moon.