Speaking of which, there just was a thread on doors in hallways:
Connecting many rooms to oneHow do I make a concealed object that is not being worn, such as a message on the wall behind a curtain (or whatever)?
You could do this specific example a couple of ways, either making the message part of the room description after the player looks behind the curtain (or making it part of the curtain description), or making a message object that the player can examine after they examine the curtain. For example:
"Secret messages - first example"
The Boudoir is a room. "Red velvet curtains and smoky candles. [if the curtains are examined] Behind the curtains someone has scrawled in sooty black, 'Beware the Man in the Black Masque!'[end if]"
A thing can be examined.
Carry out examining something: now the noun is examined.
The red velvet curtains are in the boudoir. "As dark as blood. What's this -- a secret message!". They are scenery.
test me with "look / x curtains / look"
"Secret Messages - second example"
The Boudoir is a room. "Red velvet curtains and smoky candles."
A thing can be examined.
Carry out examining something: now the noun is examined.
The red velvet curtains are in the boudoir. "As dark as blood. What's this -- a secret message!". They are scenery.
A secret message is a thing. "Behind the curtains someone has scrawled in sooty black, 'Beware the Man in the Black Masque!' "
After examining the curtains for the first time: now the secret message is in the boudoir.
test me with "look / x curtains / look"