Source: http://gizmodo.com/5977794/how-keys-work-explained-in-one-perfect-animated-gif
Ever wondered how a key opens a lock? Wonder no more. If this is not one of the best animated GIFs I've ever seen, I don't know what is. First, because it taught me something new. And then, because it's so satisfying to see it work. Aaaaaah. Oh yes. [soup—Thanks Karl!]