I've made 15 of them and 2 vests from denim shirts, and one jacket from a denim shirt. I made up my own sweatshirt jacket pattern. It is easy to use sweatshirt fabric. I also made 2 hand bags to match the jackets.
Enjoy and have a good time making one. I really like to do this because I like to pick out the fabric. I used 1 1/2 inch strips.