I remember that a few years ago, on a trip to Oxford, I watched a play called Improbable Fiction by Alan Ayckbourne. The cast of characters consists of people who meet for a session of their creative writing circle; the first act introduces both the individuals, their relationships, and their writings (a colorful assortment of genres: crime fiction, science fiction, children's books, and more). In the second act, then, during a thunderstorm, all these fictions are brought to life, and the characters find themselves in a world that has been created out of their writings.
Much of the fun in this comedy comes from the writer characters being in turn characters in their own fictions, sometimes in unlikely positions. For instance, there is Brevis, a retired schoolteacher who angrily corrects Clem (the author of complicated science fiction), whenever he misuses a foreign or technical term. Later on, when the science fiction setting has become real, Brevis is the character from Clem's fiction who utters one of these the wrong terms after the other, totally convinced and with a straight face. There was one laugh after the other from the audience. Part of what this shows, of course, is how cleverly all the fun in act II was prepared in act I.
When I just wrote that the characters find themselves in a world created out of their writings, that's not fully correct — in two ways. First, strictly speaking only one of the characters actually 'finds himself' in the strange setting. That character, Arnold, suddenly notices that his surroundings have somewhat changed, and gradually comes to understand that he is now exactly within those fictions he has heard about earlier in the evening (that is, in act I). The others haven't any noticable consciousness of the change. They just act as the characters of those fictions-within-fiction. Jess, for instance, who was in act I an aspiring writer of historical romances, is now the narrator of a Victorian fortune-hunting mystery tale, and she shows no sign of having ever been anything else than an inhabitant of that story. Arnold, on the other hand, first calls her 'Jess' and only gradually comes to understand that she now has transformed into someone else, namely a person from a fiction. So, the only character who maintains a continuity of consciousness from act I through act II is Arnold (he is, in this respect, rather in the same position as we, the audience).
The second way in which it's not quite correct to say that the characters find themselves in a world created out of their fictions is this: there are actually three alternating fictional worlds in which Arnold (and the audience) is thrown. So not all the fictions from act I are combined into only one world. However, some of them are merged: at the peak of the turbulent action in act II, in the science fiction setting, there is also suddenly an appearance of the Hoblin the Goblin (from an illustrated children's book by one of the writers), and all this happens to music which was composed by a member of the circle for a musical. So the worlds of their fictions are partially merged, partially they are held separate. There is an old Victorian setting, an early twentieth-century setting (a classical murder mystery), and finally a modern setting which has the science fiction and fantasy elements in it.
Since these alternate frequently and rapidly, how do we know in which one of them we are, at any given moment in act II? There is a strike of thunder that often signals a switch between fictional worlds, and normally there is also changed lighting and different costumes. These indicators all subtly hint at a change of setting. In part they belong to the conventions of the theatre stage — so if there is a change in lighting, we normally recognize that as a signal (for instance, it could mean that time has passed by and it's now evening where it was just mid-day, or in a more abstract setting it might mean a change to a different room, or again it might signal a temporary stepping out of the stage plot altogether, into a soliloquy designed to express some character's feelings or plans). But then on the other hand, these signals are only understood by us, the audience. What about Arnold, the character who is also drawn into those fictional worlds? I haven't checked the text of the play yet, but as far as I remember, he doesn't reflect on the change of lighting, or the difference in costume. So we can presume that these signals are meant for the audience, not for him. How does he, as a character who just traveled into a fiction, recognize that this is what happened?
In other words, what we are looking for here are passage markers: details in the world of a fiction-within-fiction which signal to a character that he has just traveled from a fiction (the world of Ayckbourn's play, in our example) to the world of a fiction within that fiction (one of the worlds of those writers circle members' fictions). In the terminology of this blog, I call such a trip a passage into some instance of unreality. Fictions, that is, stories or novels, are instances of unreality; thus, if a character travels into a world of fiction, that's called a passage into an instance of unreality. So we're looking for signals that let such a character recognize he is now within the world of a fiction. (Just to give a few more examples: other ways to travel to an instance of unreality are timetravel, where you travel into the past or the future, or entering the world of someone else's dream, as in movies like Inception. In the first case, how do you know that now you are 'in the past', or 'in the future'? If you think about it for a moment, it's not quite trivial. The same applies to dreams — what are signs that show you you're now 'within someone else's dream'? I'm not going into these other examples here, but stick with fiction. But I wanted to mention the parallel.)
If an author wants to make it clear to his character that he's been traveling into a different world (such as the world of a fiction), he builds passage markers into that world which demonstrate the fact to that character. And so did Ayckbourn. The passage marker in this case is a telephone, which sits on a sideboard throughout act I. At the beginning of act II, when we are suddenly in a Victorian setting, the phone has vanished, and promptly Arnold is perplexed when he wants to use it and notice it's gone. Then we switch to the early twentieth century and its murder mystery, and there's an old-fashioned phone sitting in the right place — but Arnold confusedly notes that this isn't his phone. In the modern science fiction setting, the phone's back where it belongs. By now everyone, including Arnold, has realized that the phone being there or not, and being a modern one or not, indicates in which world we currently are. I remember when watching the play, the first thing I looked at whenever something strange happened was the phone: a quick check to make sure I was oriented about where (in which of the fictional worlds) I was. And of course, so did Arnold on stage.