Take a horizontal strip of melinex or rag paper that is as high as you want the pocket to be deep. At the horizontal center of this strip, fold the upper right corner toward you until the top edge of the strip is vertical down the center, forming a 45° angle fold, and burnish the angle. Repeat with the left side of the strip. What used to be the left and right halves of the top of the strip should now be forming a vertical center line. Turn this whole thing over, and you now have a corner. Rick Hope that makes sense.