Negative Harmony on the Keyboard

The keyboard acts as a diagram for identifying negative harmony: the major scale is on the right, the minor scale on the left, and the arcs connect mirrored chord pairs.

The layout: Three gold keys mark the tonic - lower, middle (shared), and upper. The natural minor scale ascends from the lower tonic to the middle tonic; the major scale ascends from the middle tonic to the upper tonic. Keys outside the scale range and non-scale accidentals are grayed.

Negative Harmony: Reflecting the major-scale diatonic chords around the axis between the 3rd and 4th scale degrees produces exactly the parallel minor's diatonic chords. In C the mirror pairs are: C ↔ Cm, Dm ↔ Bb, Em ↔ Ab, F ↔ Gm, G ↔ Fm, Am ↔ Eb, B° ↔ D°.