The three tones for a triad are chosen on the basis of the so-called scale-degrees. The scale-degrees are indicated with Roman figures. On these scale-degrees the chords are stacked. In "DRIELIJN" the different tone distances between the notes of several triads and chords are clearly recognizable. Below, and on the next page, as an example mentions the chords on "c ". The stacking of triads and chords can be based on each note.
