<canvas width="600" height="400"></canvas>
<script>
var pantalla = document.querySelector("canvas")
var pincel = pantalla.getContext("2d");
pincel.fillStyle = "green";
pincel.fillRect(0,0,350,300)//cabeza
pincel.fillStyle = "black";
pincel.fillRect(50,60,90,90)//ojos
pincel.fillStyle = "black";
pincel.fillRect(210,60,90,90)//ojos
pincel.fillStyle = "black";
pincel.fillRect(140,150,70,100)//nariz
pincel.fillStyle = "black";
pincel.fillRect(100,190,40,110)//parte de la boca
pincel.fillStyle = "black";
pincel.fillRect(210,190,40,110);//parte de la boca
</script>