“Richard Feynman, an incorrigible practical joker, had his own way of dealing with security regulations. When the censors complained that his wife, Arline, now a patient at a tuberculosis sanatorium in Albuquerque, was sending him letters in code and asked for the code, Feynman explained that he didn’t have the key to it – it was a game he played with his wife to practice his code-breaking.”
