I don't see why you couldn't sew another block (like the outer blue) to each of the "corners", filling them out and making it square. You would be sewing them together across the wide edges of the blocks. In order the the weight to be right, I think you would want to duplicate that outside block. I don't see why this would not work, but I must tell you I have not actually tried it. If you do, you might let us know if it worked!