function setup() {

  createCanvas(400, 400);

  background(0);

  col = ["#212129", "#E23939", "#FFFFFF", "#000000"];

}

​

function draw() {

  background(220);

  rectangle();  

}

​

function rectangle(){

  for(let z = 0; z < 120; z++){

  e = floor(random(3))

  x1 = random(400);

  x2 = random(400);

  y1 = random(40);

  y2 = random(40);

  fill(col[e]);

  rect(x1, x2, y1, y2);

  }

}