Expanding synonyms, comparing synonyms, looking closely at duplicates, removing duplicates, and I can do a space and an outline. There was less difference between input and output than I thought: input is part and output is whole which was interesting but a part/whole can be aspects of each other: a divided line and an undivided line are still lines. A closed door and an open door is still a door.
Outline may be a state that is relative to the vestibule or room or space. Ok. This is helping my thinking even if it’s not fully making sense out of full context.