Each of twelve colors below is a chord — major, minor, suspended, seventh. Click four into the slots in any order. Hit play. The page cycles your colors as a 4-chord vamp. Save the progression via URL hash.
TEMPO · 76 BPM (2 beats per chord)
The mapping
Twelve colors, twelve chords. The mapping is hand-picked — warm colors lean major, cool lean minor, and a few sits-in-the-middle types get sus and 7th chords. Roots are spread across all 12 pitch classes so any four colors give a complete-feeling progression.
Voicing is a 4-note pad in the chord's root register: root + third + fifth + (seventh or octave depending on quality), played with a 3-oscillator soft sine voice with 80ms attack and 1.2s decay. Each chord holds for 2 beats at the chosen tempo. Default 76 BPM gives a slow ballad feel — drag tempo up to 120 for a busier vamp.
Share button serializes the four color indices and tempo into a URL hash you can paste anywhere. Anyone who opens the link hears the same progression.
Pair with /cast-wheel for the harmonic geography, /cast-letter for text-as-melody, /cast-shape for visual-as-melody. This page rounds out the input-modality trio: text, shape, color.
