Why is there a Hexagonal shaped feature on top of Saturn?


I didn't see to much about this when the flyby of (Galileo?) happened
recently.

(Alright, I'll confess I have neither a link nor am I reasonably sure
it was Galileo, and not something else, but even so)

Nobody here seemed to even notice the circulating patterns on the
'top' of Saturn are shaped like a stable hexagon.

Why?

TBerk
Aw heck, here ya go:
http://www.google.com/search?q=saturn+hexagon&btnG=Search
.