Yes, Carol. I'm sure you can do the squares any size you want and yours will end up being larger if you use the 12.5" squares, which will be nice. If you check the Flickr site (link in my first post) you'll see that several people used colors instead of the white background and Rachel also did another one all in prints, which was pretty cool! It's fun and quick, I just am not sure how to quilt it and I don't know how much I'll like the raw edges.
Anyone have any suggestions for quilting?