I also learned how hard it is to do the second side of the vest in reverse (mirror image), a problem not faced by those who stitched the design after me.
My love of pattern shows up again in the simple pinstriped background: subtle, but it lends interest to the design (as well as to the stitcher).
I gave up designing backs on vests after doing six vests. They are quite heavy, take a long time to stitch, and present some aggravating construction problems.