The ends hanging out the top make it where the purse can be closed with a piece of velcro.
You can make your own patterns theirs nothing to it make a front back and the sides any size / shape you want. Poster board, file folders, cold drink / beer cartons 20 to 24 can size are great. I rough out my patterns and use a vary form curve to clean the lines up. http://www.usa-dealer.net/Fairgate-12-112-Vary-Form-Curve-12_p_2187.html Put a center line on your pattern and make one side cut it fold it over and make the other side of your pattern.