TLRs are not rangefinder, they are reflex cameras, you focus on the ground glass using the "Viewing" lens and shoot using the taker lens, hence TWIN lens.
see HERE

IIRC There are a couple of rangefinders (Mamiya 6 comes to mind) for sqaure format.....

Quote Originally Posted by snaggs
I really like the square format. Are they rangefinders? How do you focus?