const canvas = document.createElement('canvas'),

  c = canvas.getContext('2d');

canvas.width = 500;

canvas.height = 500;

document.body.appendChild(canvas);

c.fillStyle = 'black';

c.fillRect(0, 0, canvas.width, canvas.height);

let a = 0.29, b = 0.22;

function f(x, y) {

  if (Math.random() < 0.001) b = Math.random();

  return Math.cos((x + Math.sin(x) * 0.01 + Math.cos(x * a)) * b);

}

let x = 1, y = 0;

setInterval(() => {

  if (Math.random() < 0.03) {

    x = 1;

    y = 0;

  }

  if (Math.random() < 0.001) a = Math.random();

  for (let i = 0; i < 1e3; i++) {

    x = x + f(y);

    y = y + f(x);

    c.save();

    c.translate(150, 250);

    c.scale(0.5, 0.5);

    c.fillStyle = 'rgba(255, 255, 255, 0.01)';

    c.fillRect(x, y, 5, 5);

    c.restore();

  }

}, 20);