One day, you try to escape from the drugs mafia thugs by hiding in the prison library. There you see a book called "Teach yourself karate", and you start to read it. It gets interesting, so you borrow the book and start doing the exercises in it during the evenings in your cell.
After practising karate for a few months, you start to get good at it. Next time the drugs mafia thugs gang up on you, you knock them all out with neck chops, drop kicks, and other Bruce-Lee-type activities. Next day, the thugs try to take you by surprise, but you are now so well trained in karate that you put several of them into the prison hospital. After that, the drugs mafia leave you well alone.
You find that not only the drugs mafia, but also other prisoners and even the prison guards are very respectful towards you. No one dares to contradict you or risk annoying you in any way. You are now the prison king and can do almost everything you want. You even start to believe that you could break out of prison if you wanted to.