With that pattern, you must mark your 1/4" points where everything joins on each diamond and you must stop stitching where those dots meet 1/4" away from the corner. This is not a pattern for a serger as it cannot be done. I just did a Lemoyne star quilt that had 25 12 1/2" star blocks and 80 6 1/2" star blocks and it was a stinker.