this hybrid: a hole-wall, often called a door
Walls are a nice invention but if there were no holes in them there would be no way to get in or out — they would be mausoleums or tombs. The problem is that if you make holes in the walls, anything and anyyone can get in and out (cows, visitors, dusts, rats, noise.. cold..). So architects invented this hybrid: a hole-wall, often called a door, which although common enough has always struck me as a miracle of technology. The cleverness of the invention hinges upon the hinge-pin: instead of driving a hole through the walls with a sledgehammer on a pick, you must simply gently push the door …; furthermore — and here is the real trick — once you have passed through the door, you do not have to find trowel and cement to rebuild the wall you have just destroyed: you simply push the door gently back.
Bruno Latour, Where are the Missing Masses? Sociology of a Door