For me, it may be that the toilet paper roll needs to have the open end away from the wall. I don't want to reach under the roll to take a piece! That's ludicrous!
That or my recent addiction to correcting people when they use "less" when they should use "fewer"
Isn't design language mainly used to describe general things about how a design should work?
Take Material for example. Material itself is a design language, telling you how far apart certain click targets should be, how big text should be, stuff like that, to make a generally useable UI. It doesn't tell you what shape or what colour your button should be, that's up to the implementation, like Material UI, to decide, which is what I would call the general design.