make the necessary repairs, Hawking's graduate assistant Chris Burgoyne, aided by a technician, worked a 36‑hour shift. Hawking was 40 minutes late when he arrived in Los Angeles. When he met the Simpsons staff, he apologized, saying "Sorry for being late." According to Selman, Hawking was very humble regarding the episode's jokes about him, and stated that he "took a lot of shots" at himself. The only note that Hawking gave regarding the script was that he did not want to be portrayed as drunk in the episode's last scene, in which he is discussing astronomy with Homer in Moe's tavern. Because of his motor neurone disease, Hawking was unable to speak, and he communicated using a custom-made computer. With small movements of his body, Hawking wrote a text onto the computer, which was then spoken by a voice synthesizer. Because of this, Hawking had to write all his lines on his computer, while the staff recorded them by placing a microphone in front of the computer's speaker. "It's easy to do a fake Stephen Hawking in your comedy TV show", Selman said in the DVD commentary for the episode. "Any computer can sound just like his computer, but every line that we wrote for him, he typed in himself and we recorded with our microphones as if it had come out of a regular mouth." Some of Hawking's lines were difficult to record. In particular, the word "Fruitopia" was difficult for Hawking's computer to "put together" correctly, and it "took forever" to make the word sound right from the voice synthesizer. Themes and cultural references In their book The Simpsons and Philosophy: The D'oh! of Homer, William Irwin, Mark T. Conard and Aeon J. Skoble wrote that "They Saved Lisa's Brain" in detail explores "the possibility of a utopian alternative to politics as usual in Springfield". They described "They Saved Lisa's Brain" as an "epitome" of The Simpsons diverse comedic humor, and wrote that it can be "enjoyed in two levels", as both "broad farce" and "intellectual satire". As an example of the episode's farcical humor, they referred to the episode's subplot, which, they wrote, "contains some of the grossest humor in the long history of The Simpsons." At the same time, the episode is "filled" with what they described as "subtle cultural allusions", such as the design of Mensa group's locale, which is based on the house of