Ideas:

Why is there an opening upwards? It looks like the glyph has not been completed. The Polynesian languages make a distinction between finished and non-finished actions. In e.g. Maori the continued actions can be expressed by e ... ana:
E kai ana nga tangata. The people are eating.
Kua kai nga tangata. The people have eaten.
E haere ana nga tangata inanahi. The men were going yesterday (when something happened).
Kua huihui nga tangata inanahi. The men had assembled yesterday (not complete).
Apopo e huihui ana ratou. Tomorrow they will be assembling.
Ka huihui ratou apopo. They will assemble tomorrow.
I hoki mai ratou inanahi. They came back yesterday.

(Harawira)