<canvas width="600" height="400"></canvas>
<script>
var pantalla = document.querySelector("canvas");
var pincel = pantalla.getContext("2d");
pincel.fillStyle ="darkgreen";
pincel.fillRect(0,10,350,300);
pincel.fillStyle ="black";
pincel.fillRect(50,50,90,90);
pincel.fillStyle ="black";
pincel.fillRect(210,50,90,90);
pincel.fillStyle ="black";
pincel.fillRect(140,140,70,100);
pincel.fillStyle ="black";
pincel.fillRect(100,200,40,110);
pincel.fillStyle ="black";
pincel.fillRect(210,200,40,110);
</script>
