<canvas width="600px" height="400px" > </canvas>
<script>
var pantalla = document.querySelector("canvas");
var pincel = pantalla.getContext("2d");
pincel.fillStyle = "#22b908";
pincel.fillRect(200,50,350,300);
pincel.fillStyle = "black";
pincel.fillRect(250,110,90,90);
pincel.fillStyle = "black";
pincel.fillRect(410,110,90,90);
pincel.fillStyle = "black";
pincel.fillRect(340,200,70,100);
pincel.fillStyle = "black";
pincel.fillRect(300,240,40,110);
pincel.fillStyle = "black";
pincel.fillRect(410,240,40,110);
alert("CREEPER: KA-BOOOM!");
</script>