Their 1974 U.S. chart debut (and a Top 20 LP in the UK) broke new ground with it's synth and sequencer experiments, and still mesmerizes today: Phaedra; Mysterious Semblance at the Strand of Nightmares; Movements of a Visionary, and Sequent C'.
1) Phaedra
2) Mysterious Semblance at the Strand of Nightmares
3) Movements of a Visionary
4) Sequent C'