I am working on this block to be the center square for a memory quilt for a friend who was recently diagnosed with inoperable cancer. I am still fairly new (obviously) to quilting and don't know what I did wrong on the background. I wanted an 8" block (8 1/2") finished size. What should I have done differently? I think I ran across a formula for this type of block at one point, but I can't seem to find it. Can one of you please share that with me?