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) performances were also commended, with particular praise for Roach, who was characterised as "funny, likeable and endearingly crude as Nina, then captivating and clever when the charade drops". Patrick Mulkern, writing for RadioTimes.com, also praised the "zingy funny lines" in the earlier part of the episode, and Butler commended the "smart, gentle humour" offered by the contrast between Nina and Squires. The Riddle of the Sphinx (Inside No. 9) "The Riddle of the Sphinx" is the third episode of the third series of the British dark comedy anthology television programme "Inside No. 9". It first aired, on BBC Two, on