​

function windowResized() {

  resizeCanvas(windowWidth, windowHeight);

}

​

function setup() {

  createCanvas(windowWidth, windowHeight);

}

​

function draw() {

  background(220);

  noFill();

  while(p.length < 35) p.push(pen());

  p.map(x => penOutOfBounds(x) ? penKill(x) : penTraverse(x));

  p = p.filter(({past}) => !penOutOfBounds(x) && past.length > 0);

  p.map(x => penRender(x));

}

​

function penKill({past}) {

  if(past.length > 0) past.shift();

}

​

function penOutOfBounds({x,y}) {

  return x < 0 || x > windowWidth || y < 0 || y > windowHeight;

}

​

function penTraverse(pen) {

  ({x,y,ang,t,past, speed, noiseStep, steer} = pen);

  past.push({x,y});

  if(past.length > 100) past.shift();

  pen.x += cos(ang) * speed;

  pen.y += sin(ang) * speed;

  pen.ang += map(noise(t),0,1,-steer,steer);

  pen.t += noiseStep;

}

​

function penRender({past,col}) {

  stroke(col);

  beginShape();

  past.map(({x,y}) => vertex(x,y));

  endShape();

}

​

function pen() {

  return {

    past: [],

    t: random(100),

    ang: random(2 * PI),

    speed: random(3,5),

    steer: PI * 0.25,

    noiseStep: random(0.01,0.01),

    col: random([color(255,0,0), color(255,0,255), color(0,0,0)]),

    x: random(windowWidth),

    y: random(windowHeight)

  }

}