Use the straight side of this double strip ruler to cut 1-1/2 and 2-1/2 inch strips – or use the pre-cuts that are on the market. Sew these strips together to create a 4-1/2 inch wide strip set. Turn-a-Round the ruler to cut five 60 degree triangles that finish 4 inches. Multiple layers can be cut at one time. The key holes in the ruler enable the rotary cutter to cut the angled sides without damaging the ruler.