One day, a crazy idiot stuffs you into a phone booth with four buttons, one on each wall of the booth.
You know that each button has two states, on and off. You know that if you can get all four buttons in the same state, (i.e. all on or all off) the doors will open and you will be free. However, you can't tell what state a button is in by looking at it, and you don't know the initial state of the buttons. Furthermore, every time you press a button, the booth spins around disorienting you so that you can't tell which buttons you just pressed.
You can press either one or two buttons at a time.
Is there a strategy to guarantee your escape?