Back when I was just getting started in 3D modeling I was playing around with textures and their settings. One of the things that interested me the most was how light played off certain surfaces and the surreal reflections you could get when you tweaked the settings around. About the same time it became practical to use a render setting called Radiosity that would take the light that reflected off an object and add that objects color to the reflected light creating a much more realistic render than before. Like always I figured out a way to take something that closely resembles reality and make it surreal as I can. That is how I came up with my impression of the seasons revolving around a steady black sphere. Summer, Fall, Winter, and Spring.