...but for your average (read hefty) American, the Rotator by Ron Arad is a total nonstarter.
There are some design concepts that probably should have been abandoned at the concept stage, and I would suggest that The Rotator falls into that category. Spin it so that the giant lip is at the top, and the thing becomes a shower, assuming you have a waterproof floor with a drain like in a high school locker room. Rotate it through 180 degrees however, and the big lip becomes a very uncomfortable looking banana shaped bathtub. To drain the tub, you simply rotate it back to the shower position, while trying to avoid the flood of dirty bath water cascading onto the floor.
Italian bath fittings company Teuco says they plan to manufacture The Rotator, although so far it doesn't appear on their website.