<body>
<canvas width="600" height="400"></canvas>
<script>
var tela = document.querySelector("canvas");
var pincel = tela.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.fillRect(335, 110, 90,90);
pincel.fillRect(265, 200, 70, 100);
pincel.fillRect(225, 240, 40, 110);
pincel.fillRect(335, 240, 40, 110);
</script>
</body>