"A riff will come out of.. this whole thing of do you practice at home and all that. Well, I play at home and before I knew where I was, things would be coming out and that's those little sections or riffs or whatever. At that stage it's selection and rejection. It's whether you continue with something or you go, 'No that's too much like something else,' and then you move into something else. If you've got an idea and you think that's quite interesting, then I'd work and build on it at home. "Rock and Roll" was something that came purely out of the ether."