<canvas width="600" height="400"></canvas>
<script>
var tela = document.querySelector('canvas');
var pincel = tela.getContext('2d');
pincel.fillStyle = 'darkgreen';
pincel.fillRect(0, 0, 350, 300);
pincel.fillStyle = 'black';
pincel.fillRect(50, 60, 90, 90);
pincel.fillStyle = 'black';
pincel.fillRect(210, 60, 90, 90);
pincel.fillStyle = 'black';
pincel.fillRect(140, 150, 70, 100);
pincel.fillStyle = 'black';
pincel.fillRect(100, 200, 40, 100);
pincel.fillStyle = 'black';
pincel.fillRect(210, 200, 40, 100);
</script>
