Random bathroom improvements

1. Possibility of double bath
2. Possible linoleum
3. Stics sink to the left wall instead of the middle of the bathroom
I don't think so, but if(one_in(2)) will just result in a random patchwork of tiles, while x+y%2==0 will set one color for all points where x+y is even, and another color for all points where x+y is odd.