One side of the ruler has a template to make approx. 4" finished shells. The ruler will produce a line of shells approx. 12" long. Guidelines are included for proper placement of shells. The other side of the ruler is marked so that swirls can be stitched. Use this side to created stems for vines or spines for feathers. Stitch the swirl, scoot the ruler and stitch again to create a rope or ribbon design.