<meta charset="UTF-8">
<canvas width="600" height="400"></canvas>
<script>
let screen = document.querySelector("canvas");
let brush = screen.getContext("2d");
brush.fillStyle = "Black";
brush.beginPath();
brush.moveTo(50, 50);
brush.lineTo(50, 400);
brush.lineTo(400, 400);
brush.fill();
brush.fillStyle = "white";
brush.beginPath();
brush.moveTo(100, 175);
brush.lineTo(100, 350);
brush.lineTo(275, 350);
brush.fill();
</script>
