JSFiddle - React, Tailwind, and code Playground

HTML

<canvas id="myCanvas" width="400" height="400"></canvas>

JavaScript

var canvas = document.getElementById('myCanvas');
var context = canvas.getContext('2d');
context.lineWidth = 0;
context.fillStyle = 'black';

context.beginPath();
context.moveTo(100, 100);
context.lineTo(200, 200);
context.lineTo(200, 100);
context.closePath();
context.fill();
      
context.beginPath();
context.moveTo(100, 100);
context.lineTo(100, 200);
context.lineTo(200, 200);
context.closePath();
context.fill();