What the chord is actually playing
Lamp firings
triggered on the lowest note · locked chords stand stillWhere two oscillators lock
C4 plus a second oscillator at every natural interval up to an octaveTop: how far the coupling pulls each interval at the current strength. Each sloped segment is a range of intervals captured onto the ratio above it; every interval locks to some ratio. Bottom: Arnold tongues, coloured by the ratio p:q the pair locks onto at each coupling strength (simple ratios bright; ratios with q above 24 left dark). Exact for pulse coupling; simulated when rail sag is on. Dashed line: your current coupling; blue dots: the chord you are holding.
Spectrum
live output · markers: each note as played (orange) and as designed (grey)Each oscillator is a sawtooth, the capacitor charging and the lamp dumping it, so every note brings a full comb of harmonics. When a chord locks, the orange markers leave the grey ones for just ratios, and the chord's harmonics fall onto shared lines.
Spectrogram
live output · ticks: the spectrum's markersHold a chord and watch it lock: unlocked, neighbouring lines wobble as the oscillators beat against each other; locked, every line goes still. Raise the coupling and chords further from just lock too.