It's really very simple, but it's just the way you put the HST's together. It consists of 20 HST and 5 3 1/2" blocks.
Finished block gets squared up to 15 1/2".
I've made a few goofs and sewn a few HTS's upside down. LOL But I have only myself to blame for that. I've learned now to check the diagram that I have on graph paper 1st before sewing them up.
I'm up to 15 blocks done now...(Another 41 to go.) I ran out of HTS's so I had to cut and make more. ( I don't cut all my fabric out at one time. Sometimes I need a break from the constant sewing. The eyes aren't what they use to be. It works for me.) I did 214 HTS's and now I'm ready to cut and iron them.
Wish me luck and keep the comments coming.. it helps when I'm in a slump.