Re-reading the topic I understand You referred to the shape of the piece in question.
Of course it is far more easy to construct along the axes, so four or eight lobed Mokko-forms are common (this applies to motif construction, too). However, there are many other shapes also in uneven numbers. At least they are rare but not uncommon. Your piece consists out of seven zones which seem not to be in the same size. So the artist must have used his visual judgement in the fan layout.
I’m not sure if the artists have been able to calculate angels at all. IMHO constructions in an uneven number could be evidence of a more sophisticated - or a more creative - artist.