The house dates from the period when national plumbing technology was the state of the art. In the first floor powder room, formerly a low-tech cold closet, sits an American Standard toilet that originally had a tank mounted close to the ceiling.
There's a current low-flush toilet on the second floor. The twenties model downstairs is more efficient.
Sleek it is not, but it is a miracle of hydrology and straightforward design. I have fiddled with adding clean rocks to the tank to reduce water consumption. A recent visit from a plumber, the first in my thirty-six years with this fixture, left the mechanism adjusted for minimum consumption on a major flush. I finessed the system further by replacing the heavy tank lid with a simple flap of corrugated poly sign board edged with duct tape.