Octatonic scale out, the cascading arpeggios played on the celesta in the "Sugar Plum Fairy" from "The Nutcracker" ballet are made up of dominant seventh chords a minor third apart. "Hagens Watch", one of the darkest and most sinister scenes in Richard Wagner's opera "Götterdämmerung" features chromatic harmonies using eleven of the twelve chromatic notes, within which the eight notes of the octatonic scale may be found in bars 9–10 below:] The scale also may be found in the music of Claude Debussy and Maurice Ravel. Melodic phrases that move by alternating tones and semitones frequently appear in the works of both
Diatonic scale six perfect fifths. For instance, the seven natural pitches that form the C-major scale can be obtained from a stack of perfect fifths starting from F: Any sequence of seven successive natural notes, such as C–D–E–F–G–A–B, and any transposition thereof, is a diatonic scale. Modern musical keyboards are designed so that the white notes form a diatonic scale, though transpositions of this diatonic scale require one or more black keys. A diatonic scale can be also described as two tetrachords separated by a whole tone. The term "diatonic" originally referred to the diatonic genus, one of the three genera of