I had a go with the Balkan Puzzle which is one of the February blocks of the month at Craftsy. It should have come out slightly larger than 12.5" and then be trimmed to size. Mine came out at 12" square so it's too small. I'm going to reset my 1/4" foot and try again. I looked at the discussion part of the class and quite a few folks have had the same problem. You need to use a real scant 1/4" seam.
Here's a photo of how it turned out - I have enough fabric to repeat these colour choices.