I have made two. Wash the t-shirts and do not use any fabric softener. Before sewing the t-shirts must be stabilized using a lightweight fusible interfacing. I then square up my designs so there is a one-inch margin around the design and then, using all sorts of quilting material, add strips around each t-shirt to produce a 15-inch square. I may have 2 or 3 t-shirts in a block if they are small and if the design is large I may not have any added material around a t-shirt.