It takes some time for the image to load.
One of the light sources is red.
If you are patient enough and want to switch between red light and white light, press Space bar.
Note, you may need to click on the applet before you use the keyboard.

Here are the source files:
LightSource.java
Surface.java
SecondOrder.java
HalfSpace.java
Shape.java
SurfShape.java
InterShape.java
PolyRayTracer.java
Matrix3D.java
Utility.java
PixApplet.java