I quit setting seams. I have made several hundred square in a square blocks. The second and fourth triangle added just never laid as flat as the first and the third. I never could figure out why. Then one time I just put the first triangles on and pressed them open before I put the second triangle on. That time the second triangles laid as flat as the first ones. The difference is the first ones didn't get set and because the second triangles were already on and got set when I pressed the first ones open.