Pretty Little Liars, season 2, episode 21, "Breaking the Code," aired on 20 February 2012. Spencer Hastings is played by Troian Bellisario and Wren Kingston is played by Julian Morris. Spencer: "Like?" Wren: "Like? Um... All right, I'm a touch what you'd call OCD. Every book on my bookshelf has to be in alphabetical order -- or I can't sleep." Spencer: "Then... what is Aristotle doing on the bottom row? Oh! ...It's okay. Aristotle is exactly where he should be."