One light source is red in the image on the left.
The image on the right displays the same scene highlighted with white lights.

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