1. With wrong sides together, fold each solid blue 13x21" rectangle in half to form two 10-1⁄2x13" rectangles. (The double thickness results in a more stable pillow back.) Overlap folded edges about 4" to make a 17x13" rectangle (Pillow Back Assembly Diagram). Baste across top and bottom of overlapped layers to make pillow back.
2. Layer embroidered pillow front and pillow back with right sides together; pin. Using 1⁄2" seam allowance, sew together around outer edges to make pillow cover. Turn right side out; press. Insert 12x16" pillow form through opening to complete pillow.