READ Charles Schulz's classic Peanuts comic strips closely, and you might actually hear Beethoven. Well, that is, if you can read music. A recent exhibit at the Charles M. Schulz Museum and Research Center in California unveiled a little-known secret about Schultz's piano-playing, Beethoven-loving character, Schroeder. When Schultz drew him hunched over his piano, he often added notes from actual Beethoven works. "he music is a character in the strip as much as the people are," William Meredith, the director of Beethoven studies at San Jose State University, told the New York Times. For example, in one strip from 1953, Schroeder is seen going through an intense exercise routine. He jumps rope, lifts weights and runs before sitting down to play the opening bars of Beethoven's Hammerklavier Sonata (Op. 106). What's so special about that sonata? When Beethoven handed the difficult piece to his publisher in 1819, he is believed to have said, "Now you have a sonata that will keep the pianists busy when it is played 50 years from now." The joke, then, is that Schroeder felt he needed to get into shape in order to play the piece as Beethoven intended it to be played.