Lisa's Date with Density a child from Josh Weinstein's school days who everyday would get onto the bus with a piece of toast, which had Vaseline on it. A majority of the story is a reference to the film "Rebel Without a Cause". Lisa remarks that Nelson is "like a riddle wrapped in an enigma wrapped in a vest", a reference to "a riddle wrapped in a mystery inside an enigma"; this was Winston Churchill's opinion of Russia at the outbreak of the World War II. In its original broadcast, "Lisa's Date with Density" finished 63rd in ratings for the week of December 9–15,
The Riddle of the Sphinx (Inside No. 9) and continued with "The Bill" (February 2017), the latter of which was the first of a run of five episodes, of which "The Riddle of the Sphinx" was the second. The episode was first aired on 28 February 2017. It was shown on BBC Two at 10:00pm, clashing with first episode of the third series of "Catastrophe", the acclaimed Channel 4 comedy. "The Riddle of the Sphinx" was written in the summer of 2015, one of the last of the series, and was filmed in December that year. Most of the episode was filmed in Langleybury, a country house in