Cut out the fabric into one shape (hexagons or square) and have enough piece to cover a surface 12 inches by 84 inches. Lay out and organize the pattern.
Connect each swatch around the respective conjoining edges to create a solid x by x inch piece of fabric.
Using basting spray, attach the patchwork fabric to a layer of cotton batting and a solid piece of fabric onto the other side of the cotton batting. Trim as needed.
Add top stitching as desired. For squares, going from corner to corner is standard. For hexagons, going along 2 sets of parallel edges works well.
Cut the black fabric into 2 (x by 3 inch) strips and 4 (x by 3 inch) strips. Fold over ends into the inside. Fold each strip in half so that the strips keep the same length and now have (1/2) width of the original strip (i.e., x by x).
One strip at a time, place the open end of the strip along the back of the corresponding surface. Sew into place. The strip will become a tube at this point. Fold over the strip so the folded edge is now in the front and the strip covers the edge showing the front fabric, cotton batting, and back fabric layers. Sew closed. Repeat for the other strips.