Layouts

A layout is a function from a note to one or more canvas positions — one to three on the keyboards, up to twelve on the strings. It decides where an instrument’s notes fall in Marble mode and, on the eight keyed layouts, what your fingers touch in Play mode. Switch it live in the settings; the engine keeps one implementation of the geometry, and the tablet shells draw and hit-test by asking it (the layout probe), so the circle you see is the cell you touch. Two layouts — the trumpet and the trombone — are stateful: the probe is asked with the fingering the engine holds, and the same note lands in a different cell under a different fingering.

The first eight are below; the five instruments — the trumpet and the trombone, Wicki–Hayden, the strings and the theremin — have their own page.

Circle of fifths (default; Marble-only)

Pitch class around a circle in fifths order, octave as radius — low notes outer, high notes inner. Chords become constellations; a progression walks around the dial. Not playable: adjacent wedges are a fifth apart, so a sideways bend has no semitone meaning.

Chromatic grid (playable)

Reading order, C1 at the top left to B7 at the bottom right: a row per octave, a column per pitch class, cells inset so edge drops stay on the sheet. Notes outside C1–B7 clamp to the nearest edge cell. Pitch is a function of x alone within a row, so pen legato is continuous here.

Jankó (playable)

The Jankó keyboard’s six staggered rows of whole-tone columns, every second row offset by half a column. A note stamps on all three rows of its parity — the whole lattice stays live, which is the point of visualizing Jankó. Any of the three rows plays the note; the loopback paints all three, with one ink band and one hue so they read as the same note. The semitone axis is horizontal: one semitone is half a column straight across, the same for every echo. The stagger ends are dead zones.

Piano grid (playable)

The chromatic grid’s frame with each octave as a two-row keyboard: five accidentals above at the white-key positions 1, 2, 4, 5, 6 — C♯/D♯ between their naturals, F♯/G♯/A♯ between theirs — and seven naturals below, seven octaves tall. The geometry is tuned for glissando: an accidental’s cell is 0.6 of a white key wide and 0.6 of the octave pair tall; a natural owns the bottom 0.6 of the pair. The strip above the naturals, off any accidental, is the glissando corridor — a dead zone that sustains, so a stroke through it plays the black-key run while the natural band below plays the white-key run without grazing an accidental. Tapping in the corridor plays nothing; a stroke must start on a key. Because pitch here is not a function of x alone, pen legato is quantized to real key steps — a piano glissando, by design.

Piano roll — left, right, top, bottom (Marble-only)

Four timelines, named by where the now-line sits. Left: pitch → y (low at the bottom), every drop is born at x = 0.12 and the sheet drifts to the right — a DAW timeline flowing away from the playhead. Right: the mirror, now-line at x = 0.88, the sheet drifts left. Top (Synthesia-style): pitch → x (low at the left), now-line near the top, the sheet falls. Bottom: the now-line near the bottom, the sheet rises. All four share the drift speed and the fresh-water ingress: old ink slides off the far edge, clean water enters behind the now-line. The scroll operator →

Tempo and roll speed

The rolls scroll at (bpm / 60) × roll_speed canvas lengths per second. roll_speed is canvas-lengths per beat, default 1/16: the sheet holds 16 beats — four bars of 4/4 — so at 120 BPM ink lives eight seconds. BPM is a setting the host supplies (the desktop nudges it ±5 for syncing to a metronome); midi-sink never guesses tempo from the MIDI stream.

Glides on a lattice

On the keyed layouts a one-semitone bend moves a drop exactly one cell along that cell’s own pitch axis — horizontal on the keyboards, along the string on the strings, up the pitch plane on Wicki–Hayden, to the right as the lip bend on the brass — so in Play mode the drop travels under your finger. The circle and the rolls keep a gentler rendering cap — there a bend is a gesture, not a position; the theremin’s whole width is its axis.

The thirteen

#	Layout	Keyed (playable)	Stateful
0	Circle of fifths	—	—
1	Chromatic grid	yes	—
2	Jankó	yes	—
3, 4, 6, 7	Piano roll — left, top, right, bottom	—	—
5	Piano grid	yes	—
8	Trumpet	yes	the valves (CC 110–112)
9	Trombone	yes	the slide (CC 113)
10	Wicki–Hayden	yes	—
11	Strings	yes	— (a tuning preset)
12	Theremin	continuous	—