Lots of fun with reflection and refraction! This page contains two applets illustrating a basic ray tracer, handling reflection and refraction for 2 basic object primitives, a sphere and a 3-dimensional triangle.
This first applet is just a simple collection of objects (6 spheres and 3 3-d triangles).
This second applet is a deviation from the example in class. It contains 4 objects (2 spheres and 2 3-d triangles), and is a nice demonstration of transparency and reflectance.