You are right that you can use one size to make many different size blocks--at the time I bought mine I wasn't aware of how versatile they would be. Once I receive the 9.5 HST I will be set for good. I am doing an off center log cabin with flying geese blocks in the right upper corner--I'm using both the flying geese ruler and the 4.5 HST. Believe me, it makes it much easier!