CMYK interaction built RGB + Black.
The interaction of three circles with the colors pink, yellow and blue built at the same time the subtractive model.
function setup() {
var canvas = createCanvas(500, 500);
canvas.parent('sketch');
background(255);
noStroke();
blendMode(DIFFERENCE);
// ellipseMode(RADIUS);
var i = 150;
fill(255, 0, 0);// red=cyan
ellipse(width / 1.75, height / 1.75, i, i);
fill(0, 255, 0);// green=magenta
ellipse(height / 2.5, height / 1.75, i, i);
fill(0, 0, 255);// blue=yellow
ellipse(width / 2, height / 2.5, i, i);
}
function draw() {
}