<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(0, 0, 350, 300);
pincel.fillStyle = 'black'
pincel.fillRect(50, 50, 90, 90);
pincel.fillRect(210, 50, 90, 90);
pincel.fillRect(140, 140, 70, 100);
pincel.fillRect(100, 190, 40, 110);
pincel.fillRect(210, 190, 40, 110);
</script>
