I tried to follow the tutorial
https://www.youtube.com/watch?v=SzGiC6SzelM using 6.5 inch squares for the back, 5.5 iron on interfacing ironed onto the back, and 4.5 inch center block with a 1.5 sash. My block should have come out to 6 inch square, but it was about 1/4 inch smaller. Next time I will do a smaller seam to get it to 6 inches. (It loses a lot at the folding inside out.) Also, I was surprised how much of the bottom showed, so for the future will be sure the bottom fabric is the one I want showcased. Turned out okay for this one.