Why aBernal Spheres spheres?

rounded cylinder would be a more appropriate design, so that gravity would be consistent
from one end to the other, instead of increasing as you moved towards the equator. Is
there a solid reason for the sphere shape? It's an attempt to minimize the shielding mass required (which is the lion's share of the overall mass). A sphere is the shape which encloses the maximum amount of volume with the minimum amount of surface area. It's also the most structurally efficient shape for a pressure vessel. I have a fondness for short cylinders myself. One only about twice as long as its diameter strikes me as a good compromise.