Guess who?

Richard Feynman (From Wikipedia)

"The enfant terrible among the atomic scientists was the theoretical physicist Richard Feynman, as young as he was gifted. To enrage the censors he instructed his wife to send him letters to Los Alamos which were torn into hundreds of small pieces. The officials charged with the checking of correspondence were obliged to fit all the fragments of this jigsaw puzzle together again. It also afforded Feynman great amusement to work out the combination numbers of the steel safes in which the most important data of research were kept. In one case he actually succeeded, after weeks of study, in opening the main file cupboard at the records center in Los Alamos while the officer in charge of it was absent for a few minutes. Feynman contented himself, in the brief period during which he had all the atomic secrets at his disposal, with placing in the safe a scrap of paper on which he had written, 'Guess who?' He was then able to feast his eyes on the horror of the security official as the latter perused the message which had found its way into the innermost sanctum of the Manhattan Project in some manner he was utterly unable to understand." (122) --Robert Jungk, Brighter Than a Thousand Suns: A Personal History of the Atomic Scientists