JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//cdn.rawgit.com/mrdoob/three.js/master/build/three.min.js"></script>

CSS

body {
	  margin: 0;
}

JavaScript

var views, scene, renderer;
var mouseX = 0, mouseY = 0;
var windowWidth, windowHeight;
var views = [
	{
		left: 0,
		top: 0,
		width: 0.5,
		height: 1.0,
		background: new THREE.Color( 0.5, 0.5, 0.7 ),
		eye: [ 0, 300, 1800 ],
		up: [ 0, 1, 0 ],
		fov: 30,
		updateCamera: function ( camera, scene, mouseX, mouseY ) {
			camera.position.x += mouseX * 0.05;
			camera.position.x = Math.max( Math.min( camera.position.x, 2000 ), -2000 );
			camera.lookAt( scene.position );
		}
	},
	{
		left: 0.5,
		top: 0.5,
		width: 0.5,
		height: 0.5,
		background: new THREE.Color( 0.7, 0.5, 0.5 ),
		eye: [ 0, 1800, 0 ],
		up: [ 0, 0, 1 ],
		fov: 45,
		updateCamera: function ( camera, scene, mouseX, mouseY ) {
			camera.position.x -= mouseX * 0.05;
			camera.position.x = Math.max( Math.min( camera.position.x, 2000 ), -2000 );
			camera.lookAt( camera.position.clone().setY( 0 ) );
		}
	},
	{
		left: 0.5,
		top: 0,
		width: 0.5,
		height: 0.5,
		background: new THREE.Color( 0.5, 0.7, 0.7 ),
		eye: [ 1400, 800, 1400 ],
		up: [ 0, 1, 0 ],
		fov: 60,
		updateCamera: function ( camera, scene, mouseX, mouseY ) {
			camera.position.y -= mouseX * 0.05;
			camera.position.y = Math.max( Math.min( camera.position.y, 1600 ), -1600 );
			camera.lookAt( scene.position );
		}
	}
];

init();
animate();

function init() {

	for (var ii =  0; ii < views.length; ++ii ) {
		var view = views[ii];
		var camera = new THREE.PerspectiveCamera( view.fov, window.innerWidth / window.innerHeight, 1, 10000 );
		camera.layers.set( ii );
		camera.position.fromArray( view.eye );
		camera.up.fromArray( view.up );
		view.camera = camera;
	}
	
	scene = new THREE.Scene();
	
	var geometry = new THREE.BoxBufferGeometry( 100, 100, 100 );
	var material1 = new THREE.MeshBasicMaterial( { color: 0xff0000 } ); // red
	var material2 = new THREE.MeshBasicMaterial( { color: 0x00ff00 } ); // green
	var material3 = new THREE.MeshBasicMaterial( { color: 0x0000ff } ); // blue
	
	var mesh1 = new THREE.Mesh( geometry, material1 ); // red...