The blocks finish at 6". Then there is a design idea in the back of the book to make these blocks into the centers of 12" star blocks.... optional. Also the book advises you to go to www.landauercorp.com for alternate quilt settings and also for downloadable templates for this book.
I am getting excited about this. Just putting a schedule together means that I really am going to work/play through this book and not just let it sit on the shelf!!!
hugs, Jupiter