<canvas width = "600" height = "400"> </canvas>
<script>
var pantalla = document.querySelector("canvas");
var pincel = pantalla.getContext("2d");
pincel.fillStyle = "darkgreen";
pincel.fillRect(0,0,350,300);
pincel.fillStyle = "black";
pincel.fillRect(40,50,90,90);
pincel.fillStyle = "black";
pincel.fillRect(220,50,90,90);
pincel.fillStyle = "black";
pincel.fillRect(130,140,90,90);
pincel.fillStyle = "black";
pincel.fillRect(130,150,90,90);
pincel.fillStyle = "black";
pincel.fillRect(210,180,35,120);
pincel.fillStyle = "black";
pincel.fillRect(100,180,35,120);
</script>