This is my go-to project when I am stressed with another project and need a no-think thing to do. I use deli-papers cut down to 8 1/2" and just pull pieces out of the scrap bag. If the size is right, it goes on the square, that is my only criteria for these blocks. I may have a grand mess when I finally put them together, or not. Time will tell. At this point, I think I will have to sash them.