You can ache and you can break. You can whizz and you can spin. Sometimes you're so clever, I almost think you have a twin. But tell me Brain, just where do you and me fit in?
Where do you stop and where do I begin? Who is the master, who is slave, living inside this curious cave?
If it wasn't for me then you wouldn't be you. If it wasn't for you then who would I be?