The most thrilling breakthrough of the extraordinary show is that whereas in "A Chorus Line" Michael Bennett choreographed the cast, in "Dreamgirls" he has choreographed the set. Bennett's use of plexiglass towers that dominated the set was revolutionary. The towers moved to create constantly changing perspectives and space, like an automated ballet. They energized the action, driving it forcefully along. It's why there were no set-piece dance routines in the show: dance and movement were organic to the entire action. But Bennett had made the mechanical set his dancers."