why clutter the examples with code that's the same in every sample.
See https://webgl2fundamentals.org/webgl/lessons/webgl-boilerplate.html
and https://webgl2fundamentals.org/webgl/lessons/webgl-resizing-the-canvas.html
for webgl-utils, m3, m4, and webgl-lessons-ui.
-->
<script src="resources/webgl-utils.js"></script>
<script>
"use strict";

var vertexShaderSource = `#version 300 es

// an attribute is an input (in) to a vertex shader.
// It will receive data from a buffer
in vec4 a_position;

// all shader