user: What are some good canvas libraries for browser JavaScript?

assistant: Here are some popular canvas libraries:

1. Fabric.js: This is a powerful and easy-to-use library for working with HTML5 canvas. It provides a variety of tools for creating interactive graphics and animations.
2. Konva.js: This is a 2D drawing library that provides a simple and intuitive API for creating complex shapes and animations on canvas. It's optimized for mobile devices and has excellent performance.
3. Paper.js: This is a vector graphics library that allows you to create complex shapes and illustrations with ease. It provides a variety of tools for working with paths, curves, and shapes, and supports both raster and vector graphics.
4. Three.js: This is a 3D graphics library that provides tools for creating and animating complex 3D scenes in the browser. It's ideal for creating games and interactive experiences.
5. EaselJS: This is a library that makes working with HTML5 canvas simple and intuitive. It provides a familiar display list API, similar to Flash, that makes it easy to create interactive graphics and animations.

user: could you give a hello world program for paper and three, they seem interesting

assistant: Certainly! Here's a simple "Hello, World!" program for both Paper.js and Three.js to get you started.

1. Paper.js:

First, include the Paper.js library in your HTML file:
```html
<!DOCTYPE html>
<html>
<head>
  <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/paper.js/0.12.15/paper-full.min.js"></script>
</head>
<body>
  <canvas id="myCanvas" resize></canvas>
  <script type="text/paperscript" canvas="myCanvas">
    // Create a point at the center of the view
    var point = new Point(view.size.width / 2, view.size.height / 2);

    // Create a text item with 'Hello, World!' at the center point
    var text = new PointText(point);
    text.content = 'Hello, World!';
    text.fillColor = 'black';
    text.fontSize = 30;
    text.justification = 'center';
  </script>
</body>
</html>
```
2. Three.js
```html
<!DOCTYPE html>
<html>
<head>
  <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/three.min.js"></script>
</head>
<body>
  <script>
    // Set up the scene, camera, and renderer
    var scene = new THREE.Scene();
    var camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
    var renderer = new THREE.WebGLRenderer();
    renderer.setSize(window.innerWidth, window.innerHeight);
    document.body.appendChild(renderer.domElement);

    // Create a cube
    var geometry = new THREE.BoxGeometry();
    var material = new THREE.MeshBasicMaterial({color: 0x00ff00});
    var cube = new THREE.Mesh(geometry, material);
    scene.add(cube);

    // Position the camera
    camera.position.z = 5;

    // Animation loop
    function animate() {
      requestAnimationFrame(animate);

      // Rotate the cube
      cube.rotation.x += 0.01;
      cube.rotation.y += 0.01;

      renderer.render(scene, camera);
    }

    animate();
  </script>
</body>
</html>
```
This Three.js example doesn't display the text "Hello, World!", but it creates a simple rotating cube to demonstrate how to set up a basic 3D scene with the library. To display text in Three.js, you can use additional libraries like "three-bmfont-text" or "troika-3d-text".