<canvas width = "600" height = "400"></canvas>
<script>
    var tela = document.querySelector("canvas");
    var pincel = tela.getContext("2d");
    pincel.fillStyle = "SeaGreen";
    pincel.fillRect(0, 0, 350, 300);
    pincel.fillStyle = "black";
    pincel.fillRect(45, 45, 90, 90);
    pincel.fillRect(205 , 45, 90, 90);
    pincel.fillRect(135 , 135, 70, 100);
    pincel.fillRect(95 , 190, 40, 110);
    pincel.fillRect(205 , 190, 40, 110);
</script> 
            