dreaming in spirals (color)

mySketch
xxxxxxxxxx
 
/*
author: Kevin L. Smith
​
colors from https://artsexperiments.withgoogle.com/artpalette/colors/dcdbd8-494844-21211e-0b0a09-898783
*/
const points = [];
const I = 5;
const J = 200;
const K = 100000 / J;
const color0 = [273, 9, 13, 100];
const color1 = [273, 42, 100, 100];
const color2 = [273, 20, 100, 100];
const ptSetup = xBar;
let c;
​
function xBar() {
  for (let i = 0; i <= I; i++) {
    // top-left to bottom-right
    points.push({
      x0: i * width / I,
      y0: i * height / I
    });
    // bottom-left to top-right
    points.push({
      x0: i * width / I,
      y0: height - i * height / I
    });
    // across middle
    points.push({
      x0: i * width / I,
      y0: height / 2
    });
  }
}
function grid() {
  for (let i = 0; i <= I; i++) {
    for (let j = 0; j <= I; j++) {
      points.push({
        x0: i * width / I,
        y0: j * height / I
      });
    }
  }
}
​
function setup() {
  c = createCanvas(640, 640);
  colorMode(HSB);
  noStroke();
  background(color0);
  ptSetup();
}
​
function spiral(a, theta) {
  // bounded fermat spiral
  return atan(a * sqrt(theta));
}
​
function draw() {
  if (frameCount > K) {
    return;
  }
​
  let zoom = width / I;
  const friction = 10;
  const size = 1;
​
  for (let i = 0; i < points.length; i++) {
    const point = points[i];
​
    for (let j = 1; j <= J; j++) {
      const theta = frameCount * j / friction;
      const a = 0.24;
​
      // first spiral
      let r = spiral(a, theta);
      let x = r * cos(theta) * zoom;
      let y = r * sin(theta) * zoom;
      fill(color1);
      circle(point.x0 + x, point.y0 + y, size);
​
      // second spiral
      r = spiral(-a, theta);
      x = r * cos(theta) * zoom;
      y = r * sin(theta) * zoom;
      fill(color2);
      circle(point.x0 + x, point.y0 + y, size);
    }
  }
}
/**************************************
 interaction
**************************************/
function keyReleased() {
  // press 's' to save an image
  if (keyCode === 83) {
    saveCanvas(c, 'png');
    return false;
  }
}