 Among the other pioneering thrash metal bands, one of the most important is the Canadian Voivod, with their complex and experimental style, full of psychedelic dissonances ("Dimension Hatröss" 1988, "Nothingface" 1989).The major US bands that contribute to further delineating and developing the genre are Psychotic Waltz and Dream Theater.The former, with an approach halfway between Watchtower and Fates Warning, produced "A Social Grace" (1990), melding their signature sound with the psychedelic "Into the Everflow" (1992), while the latter explored the legacy of the bands that preceded them while advancing their personal style with "When Dream and Day Unite" (1989).