That's not a moon

Setting aside the sinister function, and the fact that it's fiction, let's discuss the Death Star for a moment.

Was it built like a round-looking office building?
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Always "upright"?

Or was it designed like a planet,  the floors having a slight arc to them as they form inner layers of the circle?
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Did it have only one axis? Consider that creatures from other worlds would have worked on it.  It could have improved mobility by being able to "roll" in any direction. Consider how a professional throws a bowling ball,  for example.

I don't have a point. I'm just pondering.