Paint colour. Hear music.

The Colour Organ is a small, opinionated descendant of a four-hundred-year-old idea: that colour and sound might be the same thing wearing different clothes. Athanasius Kircher sketched it in 1646. Isaac Newton committed to a number in 1704. Louis Bertrand Castel built a cabinet with candles and stained glass in 1730. Alexander Scriabin orchestrated for a non-existent instrument in 1910 and called the staff luce.

You paint on a canvas. A scheduler sweeps it left to right at the tempo you set. Hue picks the note, height picks the octave, brightness sets the velocity, saturation opens the filter, and grey becomes percussion. Two historical mappings are on offer: Newton's seven diatonic colours and Scriabin's twelve chromatic ones, arranged by the circle of fifths.

Upload a photograph and the page reads it back as a phrase. The result is not music in any confident sense. It is the photograph speaking in the language of the chosen scheme. Occasionally beautiful. Occasionally terrible. Both useful.