trap*door
	I knew my Erik too well to feel at all comfortable on jumping
	into his house.  I knew what he had made of a certain palace at
	Mazenderan.  From being the most honest building conceivable, he
	soon turned it into a house of the very devil, where you could
	not utter a word but it was overheard or repeated by an echo.
	With his trap-doors the monster was responsible for endless
	tragedies of all kinds.
		[ The Phantom of the Opera, by Gaston Leroux ]
