Many text adventures, particularly those designed for humour (such as "Zork", "The Hitchhiker's Guide to the Galaxy", and "Leather Goddesses of Phobos"), address the player with an informal tone, sometimes including sarcastic remarks (see the transcript from "Curses", above, for an example). The late Douglas Adams, in designing the IF version of his 'Hitchhiker's Guide to the Galaxy', created a unique solution to the final puzzle of the game: the game requires the one solitary item that the player "didn't" choose at the outset of play.