First, I added a border, all the way around each block, making each block 18 inches square. I forgot to take a photo! Then I cut an 18-inch square from the front and back of each of Bob's shirts.
Before I went to NYC, I asked around and found someone who was willing to do some machine embroidery for me. She did a wonderful job.
After stitching the embroidered patches below the pockets of each shirt front, the front became the pillow cover back.
Not a great photo, but it shows Bob wearing one of these shirts last year on our cruise.
May your bobbins always be full,