So how can I design a building without doors with unilluminated spaces? What would it be like in such a space? How can we use this to design spaces where darkne

So how can I design a building without doors with unilluminated spaces? What would it be like in such a space? How can we use this to design spaces where darkness is easily preserved in set spaces without adding materials? This sounds like a lovely concept for designing a temple of some kind. Or whatever building might have rooms set aside for practicing things in darkness, like playing with one's vision or learning to do chores in the dark.