 Dream Theater's 2003 album "Train of Thought" showcased a heavier sound.This decision was inspired by the positive feedback received from their previous heavier songs on stage.1999's "" was praised for its display of old-fashioned progressive rock, and was influenced by classic conceptual rock records such as the Beatles' "Sgt Pepper's Lonely Hearts Club Band", Pink Floyd's "The Wall" and "The Final Cut", the Who's "Tommy", and Genesis's "The Lamb Lies Down on Broadway".