Tuning
Just uses the lowest note as its reference. Piano uses equal semitones.
How to play
Tap once to leave a note on; tap again to turn it off. Combine up to four notes. Each note has its own color, even when you change octaves.
Drag a knob up or down. On a computer, you can also use the arrow keys when the knob is focused.
A continuous transformation
Shape transforms the same currents from organic ink into angular forms. Blend controls how much they cross and merge. Trail controls how long the pigment lasts: turning off a note stops adding new color, while the ink already painted keeps flowing and dissolves.
This visual instrument is inspired by synesthesia, not a universal scientific mapping between notes and colors. The ink is an artistic simulation.