Cave is a moody image, drawing the eye into a dark opening. The image uses no lighting, only reflections of reflections and an agate pattern for input colour. One sphere and two planes. The sphere looks like an arch due to the skysphere reflection. I stuck with the rusting look ater experimenting with different colours for agate. I like it that way. Its also my first POVRay image. Normally I do size coding competitions in opengl and C.