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