Example 3.20

Alois Hába, Suite für vier Posaunen, Mvt. IV, Moderato cantabile, mm. 1-4

The opening of the fourth-movement chorale is harmonized with a mixture of conventional triads and seventh chords. The identification of these chords is left as an exercise for the reader. We can also observe that the outer voices move in contrary motion when the composition of the chords shifts from conventional pitches to quarter-tone pitches.