And one different way of looking at things. We all know(?) that the stars on the US flag are arranged in alternating rows of six and five. 6 + 5 + 6 + 5 + 6 + 5 + 6 + 5 + 6 = 50.
But if you look at the field at a 45 degree angle, you can see it as a sorta triangle of the odd numbers 1 + 3 + 5 + 7 + 9 = 25 (*) stars, sitting on top of the same thing flopped over.
(Teaser PDF with a few chapters.)
(* note in passing -- the sum of the first N odd numbers is N^2.)