<canvas width="600" height="400"> </canvas>
<script>
let pantalla = document.querySelector("canvas");
let pincel = pantalla.getContext("2d");
pincel.fillStyle = "red";
pincel.fillRect(0, 0, 600, 400);
pincel.fillStyle = "white";
pincel.fillRect(200, 0, 200, 400);
</script>
