Nearly P-symmetrical chords such as {B, C, Df} are considered to be extremely
dissonant. They are well-suited to static music in which voices move by small distances
within an unchanging harmony (Fig. 1D). Such practices are characteristic of recent atonal
composition, particularly the music of Ligeti and Lutoslawski. From the present
perspective, these avant-garde techniques are closely related to those of traditional tonality:
they exploit one of three fundamental symmetries permitting efficient, independent voice
leading between transpositionally or inversionally related chords.