Actually I found another on this site but, I forget where I was. It led to going to U Tube as the gal from Missouri Star quilt co took 2 blocks and put them together face to face and stitched a 1/4 inch seam all around the square, then sew from corner to corner to corner and the same on the remaining corners to form a X and low and behold perfect half square triangles. I made 3 of them this morning which made 12 inch squares for my pinwheels for a table runner. They were so cool when I got them squared up and ready to go. There was a formula on that site too. This was the largest size. I think its fast and accurate with no marking or even a tool. I am going to make a baby quilt that way. Certainly is easy. Now if I can remember where I found it on this site. It is a drag to get old. I could of passed on this. LOL Got to laugh to keep from crying.