Hi Alea.....
Fluid dynamics is one theory......no problem.
I see your point........that because Saturn is the 6th planet,
assigning a six sided shape to it is plausible......although
it has only recently been discovered,so no ancient astrologer
could have observed it.
It can therefore only be coincidence.........except Saturn also
has an Eye on it's south pole as well as the hexagram on it's
north & the Saturn talisman of ancient astrologers also
contained the Eye of Saturn.
4600 years ago in the time of Sumer the ancient astrologers
were aware of the Hexagram & Eye on Saturn & you think
that's a high probability event?
Doma.