What can move through a house without opening a single door? The wording makes you picture a person or object traveling from room to room, but the answer is something that does not need to use a doorway in the ordinary way.
Answer: Light.
Light can travel into and through a house through windows, gaps, and transparent surfaces without anyone opening a door. Sunlight can fill rooms and move across walls and floors as the position of the sun changes throughout the day.
The trick is the word “move.” It encourages you to imagine footsteps or physical movement, when the riddle is really asking you to think about something that travels naturally.
