So funny- I just bought a box of books & mags at a church sale. Scrap Quilts Galore form Oxmoor House has a 3-d 9-patch pattern by Mary Ann Keathly that looks like that. But after the 9-patches it looks like a LOT of set in seams that would drive me CRAZY. As I look at it, you might be able to use HSTs at the corners & sew the blocks together on the diagonal. Don't know for sure, but I think I would sketch it out before trying all those set in seams. IMHO