I've been meaning to the post the finishing directions for Biscornu's for quite some time now. These directions were written for me by Cathy Drolet. Thank you Cathy!
Biscornu Finishing Directions
Biscornu's can be any size. Your two designs should be the same size.
(You can use plain fabric on the back if you choose to.)
Stitch your designs leaving about 1 1/2 inch all around the design.
If your fabric is floppy (Lugana, especially the opalescent, falls into this category), or very open weave, you might want to fuse some lightweight interfacing on to the back of your fabric squares.
(Optional)
Backstitch a square border, using 2 strands of floss, around the design. Leave as many threads from the design as you wish, 2 or 3 is best. This step is very important. This backstitch border has to be the exact same length on each side (perfectly square), as you will be using it to stitch the front and back of the biscornu together. If the backstitch border is not square, you will never get your biscornu sewn together correctly.
Trim your fabric 1/2 inch from the backstitching line. (If you're suing a loose weave fabric, you might want to zigzag the edges on your machine to prevent fraying while you are joining the pieces.)
Finger press the seam allowances to the back of the stitched pieces, all four sides, along the backstitched lines.
Place pins in the exact middle of each of the sides, on both stitched pieces, at the backstitched line. If you have to count your backstitched threads to get to the exact middle, do so. It is very important to find the exact middle of the sides.
You are going to stitch your two pieces together, right side out, so you will always be able to see your backstitched line. Using two strands of floss, join one of the corners of piece 1, to the middle of one side of piece 2, using a simple whip-stitch.
Continue to join the two pieces together, stitching only under the backstitch thread on each piece, not piercing the fabric, pulling stitching thread tight enough to not leave gaps in the stitching, but not so tight that the seam is distorted, until you get to the corner. I always stitch twice through the backstitch preceding a corner, and the first one starting the next side. Line up the ext part of the seam and continue whip-stitching, until you reach the next corner. Continue around the biscorn, keeping the seam allowances to the inside, and matching the backstitch lines as you stitch the seam, from corner to corner.
As you stitch you'll see your biscornu take shape, with eight sides.
When you have only one seam left to sew, it is time to stuff with Poly Fiberfill. (If your biscornu is small, you may want to leave the last two seams un-stitched before you add stuffing.) Make sure you get stuffing right into the corners and stuff so the biscornu is full, but not overstuffed, or it will be difficult to stitch the final seam.
Stitch the remaning seam and fasten off your thread. Make sure the thread is securely fastened and run it through the biscornu and back out through a seam, tugging the thread a bit, before cutting it off where it emerges. The end will disappear back into the biscornu.
Attach your buttons, one on each side of the biscornu, directly in the middle. Use a double strand of quilting thread and thread the two ends through the eye of the needle, leaving a loop on the other end. Attach the first button to the thread, using the loop, either through the shank on the button or going through both holes on the button then putting the needle through the loop and pulling thigh (just like a look start in cross stitch.)
Push the needle through the center of the design on one side of the biscornu and out through the center of the design on the other side of the biscornu. Thread the other button onto the needle and push the needle back to the first side, pulling the thread taught to make the traditional dent in the center of the pillow. Sew through each button a couple of times, then fasten off your thread. Your biscornu is complete.
