So I toiled and struggled to sew this octagon in such a way that the center will lie perfectly flat. It didn't. I plan to take a class soon to learn how to do this. Meanwhile, I resorted to my usual coverup, an appliqued circle. I then cut the center out of the octagon, framed it in a yellow,which in retrospect should have been a bias cut, then appliqued it again to a roller coaster motif.