I used two felt circles of each color, and sewed them on with yellow embroidery thread and french knots. Then, I sewed the entire pillowcase by hand. I really felt for people in the olden days who had to do all their sewing by hand. Embroidery is one thing, but hemming, well... Anyway, it was one long piece of fabric. I hemmed each short end, overlapped them on the back, and sewed up the side seams. It didn't take as long as I feared, and maybe my hand stitching is getting more even. Maybe.