In order to accommodate students with different backgrounds, some problem sets are released in two editions: a standard edition intended for most students and a "Hacker Edition" intended for some students. Both editions essentially cover the same material. But the Hacker Edition typically presents that material from a more technical angle and poses more sophisticated questions. Most standard editions, though, are accompanied by code "walkthroughs" during which students receive direction on where to begin and how to approach the problem set. Led by Tommy MacWilliam '13, these walkthroughs were filmed in Northwest Science .