to cross the diameter of a proton. Adams rejected them all. On 3 November 1993, he gave this answer on alt.fan.douglas-adams: Adams described his choice as "a completely ordinary number, a number not just divisible by two but also six and seven. In fact it's the sort of number that you could without any fear introduce to your parents." While 42 was a number with no hidden meaning, Adams explained in more detail in an interview with Iain Johnstone of BBC Radio 4 (recorded in 1998 though never broadcast) to celebrate the first radio broadcast's 20th anniversary. Having decided it should be a number, he tried to think what an "ordinary number" should be. He ruled out non-integers, then he remembered having worked as a "prop-borrower" for John Cleese on his Video Arts training videos. Cleese needed a funny number for the punchline to a sketch involving a bank teller (himself) and a customer (Tim Brooke-Taylor). Adams believed that the number that Cleese came up with was 42 and he decided to use it. Adams had also written a sketch for The Burkiss Way called "42 Logical Positivism Avenue", broadcast on BBC Radio 4 on 12 January 1977 – 14 months before The Hitchhiker's Guide first broadcast "42" in Fit the Fourth, 29 March 1978. In January 2000, in response to a panellist's "Where does the number 42 come from?" on the radio show Book Club, Adams explained that he was "on his way to work one morning, whilst still writing the scene, and was thinking about what the actual answer should be. He eventually decided that it should be something that made no sense whatsoever – a number, and a mundane one at that. And that is how he arrived at the number 42, completely at random." Stephen Fry, a friend of Adams, claims that Adams told him "exactly why 42", and that the reason is "fascinating, extraordinary and, when you think hard about it, completely obvious." However, Fry says that he has vowed not to tell anyone the secret, and that it must go with him to the grave. In an interview at the Sydney Opera House in 2010, two minutes before the end of the show, Fry appears to be ready to reveal the answer, but remains inaudible due to an apparent failure of the microphone. John Lloyd, Adams' collaborator on The Meaning of Liff and two