<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>CANVAS</title>
</head>
<body>
<canvas width = "600" height = "400"></canvas>
<script>
var pantalla = document.querySelector("canvas");
var pincel = pantalla.getContext("2d");
pincel.fillStyle='black';
pincel.beginPath();
pincel.moveTo(50, 50);
pincel.lineTo(50, 400);
pincel.lineTo(400, 400);
pincel.fill();
pincel.fillStyle='white';
pincel.beginPath();
pincel.moveTo(100, 175);
pincel.lineTo(100, 350);
pincel.lineTo(275, 350);
pincel.fill();
</script>
</body>
</html>
