The Clairvoyant
The clairvoyant goes out of the room, undertaking to name the person whom his confederate shall point out.
The door being shut upon the clairvoyant the confederate points to one whom we will call Mr. B.
“At whom am I pointing?” he queries.
“At Mr. B.,” replies the clairvoyant.
The trick is for the clairvoyant and his confederate to arrange between them that the person who speaks last before the clairvoyant leaves the room is the person to be pointed at.