I saw an attic window wallhanging made from a panel at a show. It was pretty but distorted. Unfortunately, the quilter did not account for the thickness of the window, so all the horses looked like they were an extra few feet long. She took the panel and simply split it, then sewed the window pieces to each side. The picture only "lost" 1/2" from seam allowance where it needed to lose the 2" (or so) from the window. If you use realistic fabrics, you may want to keep that in mind (unless you already know).