As a final for this excursion we should notice Aa6-63 at day 572:

 

Aa6-63	Aa6-64	Aa6-65	Aa6-66 (1146)
day 572		day 0

 

The glyph resembles Gb5-10:

 

Gb5-6 (360)	Gb5-7	Gb5-8	Gb5-9	Gb5-10

 

Presumably the idea is to illustrate the open mouth (vaha kai) at the western horizon ready to swallow the old season. If we count from Ga1-1, the ordinal number will be 363 for Gb5-10, a number looking quite similar to 663.