LEGO builder Akiyuki has created the LEGO GBC Module: Planets, a great ball contraption that makes balls appear to move in orbit around planets.
The 3rd GBC module using antenna parts (ID 3957). Hemisphere parts with planets pattern of Star Wars Series are used as decoration. A prototype of the module had no decoration of planets. Fortunately, I happened to find the hemisphere parts at my working table which were kept for another purpose, and I could attached them. The module represents that the balls go around each planet and move to the next planet as if a spacecraft traveled around planets in a solar system.
photos via Akiyuki