Buenos días, adjunto la solución al ejercicio creeper:
<canvas width="600" height="400">
</canvas>
<script>
var pantalla = document.querySelector("canvas");
var pincel = pantalla.getContext("2d");
pincel.fillStyle = "lightgrey";
pincel.fillRect(0,0,600,400);
pincel.fillStyle = "darkgreen";
pincel.fillRect(125,50,350,300);
pincel.fillStyle = "black";
pincel.fillRect(175,110,90,90);
pincel.fillStyle = "black";
pincel.fillRect(335,110,90,90);
pincel.fillStyle = "black";
pincel.fillRect(265,200,70,100);
pincel.fillStyle = "black";
pincel.fillRect(225,240,40,110);
pincel.fillStyle = "black";
pincel.fillRect(335,240,40,110);
</script>
