The ultimate summer nap: Create a curl-up space with room for a double-size air mattress
Fold selvage to selvage (see figure). Cut top 3 inches from fold; cut bottom 31½ inches from fold. Repeat to cut both pieces as shown.
Fold seam to outside and top-stitch. Hem top 1/2 inch, turn again 1/2 inch, stitch. Hem bottom 1/2 inch, turn again 1/2 inch, stitch.