Wow, that opened up a lot of discussion about pressing seams open vs. pressing to one side. I came from a clothing construction background so I always pressed seams open. I started quilting in the late 1950's there weren't very many books about quilting. I learned from the McCalls Needlework and Craft magazines and trial and error. I think the pressing to one side came from the hand quilters. They did it so the batting wouldn't escape out of the seams, which it might do if they were pressing the seams open. Batting has changed a lot since then and machine stitching is more even and tighter. Therefore I feel we are justified to do what works best and not consider either method a "rule". As you can see above, I pressed seams to one side so they would butt up against the other seam when sewing the 4 triangles together. I also did that for the seams when sewing the quarters together. The drawback to the seams pressed open is that you don't have the ditch to quilt in. I like ditch quilting to emphasize the geometric shapes in a lot of quilts, especially wall hangings.