A Chinese automaker just filed a patent for car seats with a hidden loo

. A toilet body sits hidden beneath the car seat, mounted on a sliding rail system. When you need it, you use the rail system to pull it out. When you are done, you slide it back under the seat. The whole thing is designed to take up as little space as possible, which matters a lot in small cars and electric vehicles where battery packs already eat up most of the room under the floor. Getting a patent is one thing, but actually building this into a car is another. The engineering challenges are significant: drainage pipes need to...