You can add triangles to each side of the block (to make it square in a square). If blocks are still not large enough, add rectangles (width needed or multiples to get width desired, like a log cabin) to each side. Hope this is clear. If not, maybe someone could draw this out to illustrate.
I love to make QOV as I am the mom of a Marine (1996-2005). Two of my QOVs were given to veteran's this year on 11/11.