I make triangles by sewing in the middle, not just one time but 2. Make the square 1/2 inch larger than you want the triangle to be. Sew 1/4 inch to one side of the center mark, turn around and sew 1/4 inch on the other side of the center mark. Cut in half on the center mark. You have 2 sets of traingles already attached==light on dark, dark on dark, or whatever you match with right sides together.