I think that someone could appreciate the abstract beauty of Bach's works by looking at the sheet music

When Hofstadter wrote about the Tortoise and the Disk he was being tongue-in-cheek. But he also did a column in Metamagical Themas, during the couple of years he took over for Martin Gardner in Scientific American, in which he stressed the visual beauty of Chopin piano scores, distinct from their musical charm. And I think he meant it that time.