Richard Feynman

one of my diseases, one of my things in life, is that anything that is secret I try to undo. And so the locks to those filing cabinets represented a challenge to me. How the hell to open them? So I worked and worked on them. There are all kinds of stories about how you can feel the numbers and listen to things and so on. That's true; I understand it very well - for old- 19 fashioned safes. But these had a new design so that nothing would be pushing against the wheels while you were trying them, and none of the old methods would work. I read books by locksmiths, which always say in the beginning how they opened the locks when the safe is under water and the woman in it is drowning or some-thing, and the great locksmith opened the safe. And then in the back they tell you how they do it, and they don't tell you anything sensible. It doesn't sound like they could really open safes that way — like guess the combination on the basis of the psychology of the person who owns it! So I always figured they were keeping the method a secret, and like a kind of disease, I kept working on these things until I found out a few things. First, I found out how big a range you need to open the combination, how close you have to be. And then I invented a system by which you could try all the necessary combinations - 8,000, as it turned out, because the woman DROWNING عزه Books are always telling how the great locksmith opens the safe under water when the woman in it is drowning. 20 you could be within two of every number. And then I worked out a scheme by which I could try numbers without altering a number that I had already set, by correctly moving the wheels, so that I could try all the combinations in eight hours. And then finally I discovered (this took me about two years of researching) that it's easy to take the last two numbers of the combination off the safe if the safe is open. If the drawer was pulled out, you could turn the number and see the bolt go up and play around and find out what number it comes back at, and stuff like that. With a little trickery, you can get the combination off. So I used to practice it like a cardsharp practices cards, you know - all the time. Quicker and quicker and more and more unobtrusively I would come in and talk to some guy. I'd sort of lean against his filing cabinet, and you wouldn't even notice I'm doing any-thing. I'm not doing anything— just playing with the dial, that's all, just playing with the dial. But all the time I was taking the two numbers off! And then I would go back to my office and write the two numbers down, the last two numbers of the three. Now, if you have the last two numbers, it takes just a minute to try for the first number; there's only 20 possibilities, and it's open. OK? It takes about three minutes to open a safe if you know the last two numbers. So I got an excellent reputation for safe-cracking.

the colonel said I shouldn't tell them how the neutrons work and all the details because we want to keep things separate, so just tell them what to do to keep it safe.