<canvas width="600" height="500"></canvas>
<script>
var pantalla = document.querySelector("canvas");
var pincel = pantalla.getContext("2d");
pincel.fillStyle = "green";
pincel.fillRect(0,0,600,500);
pincel.fillStyle = 'black';
pincel.fillRect(90, 100, 140, 120);
pincel.fillRect(380, 100, 140, 120);
pincel.fillRect(230, 220, 150, 200);
pincel.fillRect(380, 310, 80, 300);
pincel.fillRect(150, 310, 80, 190);
</script>