JSFiddle - React, Tailwind, and code Playground

HTML

<head>
  <meta charset="utf-8">
  <title></title>
  <script>
window.onload = function () {
	var canvas = document.getElementById("canvas");
	var ctx = canvas.getContext("2d");
	ctx.moveTo(10,10);
	ctx.lineTo(90,10);
	ctx.lineTo(90,90);
	ctx.lineTo(10,90);
	ctx.save();
	ctx.scale(0);
	ctx.lineTo(45,45);
	ctx.closePath();
	ctx.restore();
	ctx.strokeStyle= "black";
	ctx.stroke();
}
  </script>
  <style>

  </style>
</head>
<body>
<canvas id="canvas"></canvas>
</body>