fastNoise

function fastNoise(canvas) {
  canvas.width = 300;
  canvas.height = 300;
  const totalPixels = canvas.width * canvas.height * 4;
  const ctx = canvas.getContext("2d");
  const arr = new Uint8ClampedArray(totalPixels);

  for (let i = 0; i < arr.length; i += 4) {
    let r1 = (Math.random()>=0.5) ? 255 : 0; 
     arr[i + 0] = r1;
     arr[i + 1] = r1;
     arr[i + 2] = r1;
     arr[i + 3] = r1 === 255 ? 0 : 100;
  }

  let imgd = new ImageData(arr, canvas.width, canvas.height);
  ctx.putImageData(imgd, 0, 0);
}