<canvas width="600" height="600">
</canvas>
<script>
var screen = document.querySelector("canvas");
var pincel = screen.getContext("2d");
pincel.fillStyle = "green";
pincel.fillRect (50,50,400,400);
pincel.fillStyle = "black";
pincel.fillRect (120,120,90,90);
pincel.fillStyle = "black";
pincel.fillRect (300,120,90,90);
pincel.fillStyle = "black";
pincel.fillRect (210,210,90,150);
pincel.fillStyle = "black";
pincel.fillRect (170,300,50,150);
pincel.fillStyle = "black";
pincel.fillRect (300,300,50,150);
</script>
Resultado: Creeper