I'm visiting my brother In Florida, in case that makes a difference.
His new place is not really that new, 10 years at least, I think. But the toilet works differently from all other toilets.
My toilet and others I've seen, when you flush, fill the bowl with water, (it swirls around (but maybe that does not matter) and when there is enough, it overflows the trap and the draining water sucks out most of the water in the bowl. There is an empty vortex in the middle but the doughnut of swirling water is at least 2 inches from the very outside to the empty center hole.
Wth this toilet, barely any water seems to have entered the bowl, there is no visible swirling, no visible extra water except possibly a thin layer running from the rim to the water line, and right at the start, everything leaves the bowl. It takes no more than 3 seconds. What's up?
It's American Standard. FWIW, the crosssection of the tank when viewed from the top is like a D, with the bulge facing the user.
- It's not a pneumatic toilet like some I've seen, maybe in hotels or some public bathroom. Instead, it has the same Fluidmaster valve my toilets have and the same flapper.