I agree with lollygagging about having a narrow first border , the piano keys, ant then an outer boarder but I would throw in some other, less strong colors. If you have some of the focal fabric, it would be good to include that in the piano keys -- I would also use whatever is the background of the focal fabric(white or beige). I do a lot of piano keys and I find that when you use such strong fabrics, it helps to use a print that is in the quilt as well.