<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<canvas width="600" height="400">
</canvas>
<script>
var pantalla = document.querySelector("canvas");
var pincel = pantalla.getContext("2d");
//1
pincel.fillStyle ="darkgreen";
pincel.fillRect(0, 0, 350, 300);
//2
pincel.fillStyle = "black";
pincel.fillRect(50,60,90,90);
//3
pincel.fillStyle = "black";
pincel.fillRect(210,60,90,90);
//4
pincel.fillStyle = "black";
pincel.fillRect(140,150,70,100);
pincel.fill();
//5
pincel.fillStyle = "black";
pincel.fillRect(100,190,40,110);
pincel.fill();
//6
pincel.fillStyle = "black";
pincel.fillRect(210,190,40,110);
pincel.fill();
</script>
</body>
</html>