The shower is positioned right in the center of the room.
Unlike the Japanese, who don't feel they've bathed unless they soak in the tub, a shower which Americans can wash off their sweat over and over again, is a must for them.
This will make it possible for others to use the vanity while a person is taking a shower.
It might be possible to build it even in Japan if a building has about 330㎡ of floor space. But it would be difficult because there's no designer who's got this idea (laughing).