These stamps were designed to make it possible to sew irregular shapes to together on a sewing machine. The pieces interlock but because both the cutting lines and the 1/4" sewing line is stamped onto the fabric which makes it easier to line up the edges and sew on a sewing machine. With the seam lines stamped onto the back of the fabric, the sewing can start and stop at the corners, (not sewn off the fabric) making it possible to fit the other piece in. There are some “Y” seams but it makes it much faster to sew on a sewing machine instead of doing hand stitching like English Paper Piecing. Videos are available on my YouTube channel explaining and demonstrating this method. Many of the videos with demonstrate step by step as well as show how to sew some of the quilt blocks designed using these stamps.