thing to do. Everyone here was surprised and saddened by her death." Directing and animating The episode was directed by Mark Kirkland, who was intrigued by the story because he had not seen many television episodes about vegetarianism. The designs for Paul and Linda McCartney are unusual for The Simpsons in that the characters have brown and blue irises, respectively. Most The Simpsons characters simply have black spots in the centers of their eyes. In one scene of the episode, Homer sprays two bottles of lighter fluid onto his grill, causing viewers to anticipate an explosion when Homer throws a match on it. When he does release the match, however, the grill barely ignites. A similar scene appears in an older episode of The Simpsons, "Treehouse of Horror", although in that episode, Homer uses a single bottle of lighter fluid and causes an explosion. Mirkin enjoyed the joke enough to reuse parts of it in "Lisa the Vegetarian", adding new twists to further enhance the comedic effect. The old sketches from "Treehouse of Horror" were used to help the animators animate the scene. Cultural references The episode features several references to the Beatles and McCartney's solo career. For instance, McCartney tells Lisa that playing his 1970 song "Maybe I'm Amazed" backwards will reveal "a recipe for a really rippin' lentil soup". A modified version of the song plays in the final scene, then over the closing credits of the episode; when played backwards, McCartney can be heard reciting the recipe in the song. Mirkin had McCartney record the recipe, which was later added in reverse over the original song. McCartney thought it was "very funny" that the staff wanted to "send up the whole cult thing" of backmasking on the Beatles' songs. "A secret lentil soup recipe seemed a nice parody of that", he said. One of the backwards snippets says, "Oh, and by the way, I'm alive", a reference to the "Paul is dead" urban legend. When Lisa, Apu, and the McCartneys gather on the Kwik-E-Mart roof, Apu tells Lisa, "I learned long ago to tolerate others rather than forcing my beliefs on them. You know, you can influence people without badgering them always. It's like Paul's song, 'Live and Let Live'." Paul corrects Apu and says the song's title is actually "Live and Let Die". The McCartneys later ask Lisa if she would like to hear a song,