webgl-lessons-ui.js"></script>
<script src="../../resources/webgl-utils.js"></script>
<script src="../../resources/lessons-helper.js"></script> <!-- you can and should delete this script. it is only used on the site to help with errors -->
<script>
"use strict";

function main() {
  const opt = getQueryParams();
  const ctx = document.querySelector("canvas").getContext("2d");

  const maxDepth = opt.maxDepth ? parseInt(opt.maxDepth) : 4;
  const dotRadius = 5;
  const selectRadius = dotRadius * 2;
  const s