I am writing a science fiction story about a strange universe. I have a few questions which fall in the same general category. 1) What sort of gravity would allow a planet to maintain the shape of a dodecahedron? 2) If there exists a planet, where the physical laws are the same as in this universe, can such a planet maintain the shape of a doughnut (or more scientifically, a toroid)? Would gravity or centrifugal forces cause it to collapse into something more spherical? 3) What sorts of problems, given the known laws of this universe would there be in creating some kind of force field (electro-magnetic or otherwise) in a bubble surrounding yourself, and using that bubble to fly? 4) Since the electro-magnetic force is more powerful than gravity, is it possible to somehow convert electro-magnetic energy directly into gravity and make an effective anti-gravity device?