Ivan Wyschnegradsky, Prelude No. 16, mm. 1-3
In Prelude No. 16, the tonic tetrachord helps determine the shape of the melodic line. The opening phrase of this unaccompanied melody outlines the third B-quarter-flat to D-quarter-flat. D-quarter-flat is enharmonically equivalent to C-three-quarters-sharp. Wyschnegradsky gives C-three-quarters-sharp as the canonic spelling in his Mode XVI but substitutes the D-quarter-flat throughout this prelude.