 So this was something that plenty of artists did something kind of like that, usually just in the form of cover songs, like all the bands of their era, like the Beatles and the Stones and such. So Led Zeppelin were unusual in that they were a jam band. They would play these long songs sometimes. They would improvise them on stage, and there'd be like sections to the song where you're doing this thing, and then you do something else, and you do something else, rather than just being a nice, compact three-minute song.