<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Programa</title>
</head>
<body>
<canvas width="600" height="400"></canvas>
<script>
var pantalla = document.querySelector("canvas");
var pincel = pantalla.getContext("2d");
pincel.fillStyle = "green";
pincel.fillRect(0,0,370,370);
pincel.fillStyle = "black";
//ojos
pincel.fillRect(45,60,90,90);
pincel.fillRect(225,60,90,90);
//nariz
pincel.fillRect(135,148,90,120);
//boca
pincel.fillRect(95,200,40,120);
pincel.fillRect(225,200,40,120);
</script>
</body>
</html>