Strip tubing basically sews two 2.5" strips together, and then lays a 4.5" (or another set of 2, 2.5" strips sewn together) on top, stitch down both sides to form a tube, then cut into 45 degree tirangles, reversing the ruler with each piece cut. There is a TUTE on the Missouri Star Quilt Company web site that shows how to do these...........really neat when you use scraps.....