const num = 1000;

const noiseScale = 0.01 / 2;

​

function setup() {

  createCanvas(850, 600);

  for (let i = 0; i < num; i++) {

    particles.push(createVector(random(width), random(height)));

  }

  stroke(255, 60); // adjust the last number for the transparency of the strokes

  strokeWeight(5); // adjust the thickness of the strokes

  clear();

​

}

​

function draw() {

  background(0, 3); //the smaller the last number is, the longer the strokes stay visible + the slower the background color switches.

​

  for (let i = 0; i < num; i++) {

    let p = particles[i];

    point(p.x, p.y);

    let n = noise(

      p.x * noiseScale,

      p.y * noiseScale,

      frameCount * noiseScale * noiseScale

    );

    let a = TAU * n;

    p.x += cos(a);

    p.y += sin(a);

    if (!onScreen(p)) {

      p.x = random(width);

      p.y = random(height);

    }

  }

}

​

function mouseReleased() {

  noiseSeed(millis());

}

​

function onScreen(v) {

  return v.x >= 0 && v.x <= width && v.y >= 0 && v.y <= height;

}

​