Mi solución
<!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>
let pantalla = document.querySelector('canvas');
let pincel = pantalla.getContext('2d');
pincel.fillStyle = 'green'; // Propiedad
pincel.fillRect(0,0,350,300); // funcion
pincel.fillStyle = 'black';
pincel.fillRect(50,45,90,90);
pincel.fillStyle = 'black';
pincel.fillRect(215,45,90,90);
pincel.fillStyle = 'black';
pincel.fillRect(140,135,75,100);
pincel.fillStyle = 'black';
pincel.fillRect(215,190,40,110);
pincel.fillStyle = 'black';
pincel.fillRect(100,190,40,110);
</script>
</body>
</html>
