function setup() {

  createCanvas(400, 400);

  background(220);

  zoff = 0.0;

}

​

function draw() {

  loadPixels()

  let xoff = 0.0;

  for (let y = 0; y < height; y++) {

    let yoff = 0.0;

    for (let x = 0; x < width; x++){

      let index = 4*(x+y*width);

      let brightness = map(noise(xoff, yoff, zoff), 0, 1, 0, 255);

​

      pixels[index] = 105;

      pixels[index+1] = 100;

      pixels[index+2] = brightness;

      yoff += .01;

    }

    xoff += .01;

  }

  zoff += .01;

  updatePixels();

}