Comment by glenstein

>I'm curious why there's no clear "Spanish" in these ISBN visualizations

I had the exact same question, and I do have a completely unsupported theory. There's one large block that appears to be Argentina, or possibly Peru, although their titles are on the fringes of the large block. The block is otherwise unlabled, no name sitting at the center of the block like you see with the other major ones. I would be slightly surprised if it were entirely argentina, but it would make a lot of sense if that block were Spanish.