function setup() {
  createCanvas(160, 160);
}

function tekenPixels(pixels) {
  for(var i = 0; i < pixels.length; i++) {
    for(var j = 0; j < 4; j++) {
      fill(pixels[i][j]);
      strokeWeight(0);
      rect(j*40, i*40, 40, 40);
    }
  }
}

function draw() {
  background(220);
 
  var pixels = [
    [color(255, 0, 0), color(255, 255, 255), color(255, 255, 255),color(255, 255, 255)],
    [color(255, 255, 255),color(0, 255, 0),color(255, 255, 255),color(255, 255, 255)],
    [color(255, 255, 255),color(255, 255, 255),color(0, 0, 255),color(255, 255, 255)],
    [color(255, 255, 255),color(255, 255, 255),color(255, 255, 255),color(100, 200, 50)]
  ];
 
  tekenPixels(pixels);
}