the teleplay was written by Steve Holland, Maria Ferrari, and Adam Faberman. The episode was directed by Mark Cendrowski. It features a guest appearance of Wayne Wilderson as Travis, in addition to South-African American entrepreneur and business magnate, Elon Musk as himself. It first aired in the US on CBS on November 19, 2015, and first aired in the UK on E4 on December 17, 2015. Reception Ratings The episode was watched live by 15.19 million viewers, and had a ratings share of 3.8, during its original broadcast in the US. The 7 day data showed the episode received a total of 21.23 million viewers. Its UK premiere received 2.285 million viewers (7 day data), with the expanded 28 day data receiving 2.515 million viewers, making it the most watched programme on E4 for the week. Critical response "The Platonic Permutation" received mixed reviews from critics. Critics praised Sheldon and Amy's storyline but were critical of the other two subplots. IGN Jesse Schedeen said of Sheldon and Amy's storyline saved the episode from "total mediocrity". Caroline Preece of Den of Geek praised Sheldon and Amy's storyline as well, saying the other two subplots resolution's had "left something to be desired". Digital Spy Tom Eames said of "The Platonic Permutation": "Aside from a couple of sweet scenes with Sheldon and Amy, this was one of those episodes where you'd have a better time if you just looked at the photos and caught up on the synopsis on Wikipedia". Schedeen opined that the soup kitchen storyline had potential but ultimately said it lacked humour. He and Eames criticized the lack of message for viewers about being thankfulness or generous and said that Howard's selfishness is instead rewarded by meeting Elon Musk. Preece was critical of the subplot saying Howard was "misused" by "providing lazy comedic relief to compensate for some of the more dramatic things" the show has done in "The Platonic Permutation" and the wider season. Schedeen criticized Musk's appearance by saying he was not put to "very good use" and that his interactions with Howard were stiff and awkward. Eames concurred calling his appearance a "bit pointless and self-indulgent" and criticized his acting abilities. Schedeen said the Leonard and Penny's subplot was mildly more entertaining that of the soup kitchen but said parts of it felt repetitive. Eames concurred calling the storyline "mildly funny". Schedeen praised Sheldon and Amy's storyline