There are several different blocks. People made their favorite 9" block, then they were all put together and borders added.
churn-dash variation
flying geese
pinwheel
friendship star
I put a zig zag line in the narrow white border, with another line going out to the corner
there is a simple meander with navy thread in the dark outer border.
Nothing fancy would show, so I kept it simple here
the backing is a great patriotic print: