Appears that the design is cut to shape, without any seam allowance and then a length of twine is added by machine using a wide zigzag stitch to the outer edge. The piece is then finished with a felt backing which has had it outer edge pinked. Effective, but a little messy with the machine stitching - think I would hand blanket stitch having first turned under a small seam allowance.
Solo Patrones Punto Cruz
Solo Patrones Punto Cruz (pág. 603) | Aprender manualidades es facilisimo.com