If you take 2 + 3 + 2 inch (total 7in) strips and sew them together with an exact scant 1/4" you will wind up with a 6" width. Then you would cut the length to get 6" blocks unless your strips were 6" long. If you get more or less than 6" when you sew the strips together, you need to readjust your 1/4" and try again. The extra is taken up in your seams.