Ganymed - moon of Jupiter. Tom and Dave are building a space station. The base and solar modules have already been constructed. Taking turns, Tom and Dave have to place tubes, move through tubes or space. The astronaut who picks up more valuable counters and returns to his base more quickly with his two solar counters wins the game. Tom Tube presents a new kind of tessalation with rhombs and triangles, creating a complex, mind puzzling structure of ways through space.