Google "Disappearing Nine Patch" and the tutorials will pop right up. (They're free).
According to tuts, you can just use any fabrics. I used this material for my sample because it was left from a back I made for a quilt for church charity. The print was what was left from a king-size sheet a friend bought at a yard sale. Hardly used at all! One of the video tuts suggests charm packs. Have fun. Sal