> Volvo is perhaps the ultimate example in good UI for the AC: the buttons are shaped like a human, and you press the part of your body where you want air:
It's nice, but it still a major issue: you need to look at it while pressing it to know state.
If, instead, it's three stacked buttons top to bottom, you don't have to do that.
My car (and many older cars) simple has two knobs. One for temperature, one for location. If you entered a tunnel, you just crank the right hand knob all the way over to defrost. Better than buttons.
It's nice, but it still a major issue: you need to look at it while pressing it to know state.
If, instead, it's three stacked buttons top to bottom, you don't have to do that.