Focus – Moving Waves (1971):  Focus is a long-lived progressive rock band from Holland that was formed in 1969.  Moving Waves is their second album and features their biggest hit song (at least in this country), “Hocus Pocus”, a mostly instrumental song with frequent outlandish vocalizing by keyboardist, flautist and vocalist Thijs van Leer.  Side 2 is a group of inter-connected songs collectively called “Eruption” of the sort that often appears on progressive rock albums.