const c = document.body

  .appendChild(document.createElement('canvas'))

  .getContext('2d');

Object.assign(document.body.style, {

  margin: 0,

  height: '100%'

});

Object.assign(c.canvas.style, {

  position: 'absolute',

  left: 0,

  top: 0,

  width: '100%',

  height: '100%'

});

let t = 0;

function resize() {

  c.canvas.width = innerWidth * 2;

  c.canvas.height = innerHeight * 2;

  draw();

}

window.addEventListener('resize', resize);

resize();

function draw() {

  const {

    canvas: { width, height }

  } = c;

  c.fillStyle = 'rgba(155, 155, 155, .4)';

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

  c.fillStyle = '#000';

  let x = innerWidth;

  let y = 0;

  t += 0.05;

  for (let i = 0; i < innerHeight; i++) {

    x += 2 * Math.cos(t + i * 0.1 * Math.cos(i / 200));

    y += 2;

    c.fillRect(x, y, 100, 1);

  }

}

function loop() {

  draw();

  window.requestAnimationFrame(loop);

}

loop();