Lockheed rotating space station:2

A closeup of part of the “wheel” of the early-60’s Lockheed space station concept. Via NASA history office.

A number of early rotating space stations used “wheels” like this, with straight cylindrical segments forming a torus. While this would be relatively easy to build, it would have the result that the flat floors would be “curved” from the standpoint of “gravity.” Things would roll “downhill” towards the joints between segments.