Chromatic circle "discrete" structure, and there is no obvious way to assign pitch classes to each of its points. A pitch constellation is a graphical representation of pitches used to describe musical scales, modes, chords or other groupings of pitches within an octave range. It consists of a circle with markings along the circumference or lines from the center which indicate pitches. Most pitch constellations use of a subset of pitches chosen from the twelve pitch chromatic scale. In this case the points on the circle are spaced like the twelve hour markings on an analog clock where each tick mark represents
Diatonic scale the ancient Greeks. In musical set theory, Allen Forte classifies diatonic scales as set form 7–35. This article does not concern alternative seven-note diatonic scales such as the harmonic minor or the melodic minor. Western music from the Middle Ages until the late 19th century (see common practice period) is based on the diatonic scale and the unique hierarchical relationships created by this system of organizing seven notes. There is one claim that the 45,000-year-old Divje Babe Flute uses a diatonic scale, but there is no proof or consensus it is even a musical instrument. There is evidence that the