Recursive Reality



""To understand recursion, one must first understand recursion.""

Multiple worlds that exist side-by-side are fairly common in fantasy and speculative fiction, but sometimes things get more complicated than one dream world, Another Dimension, a simple Alternate Universe, or just one Show Within a Show.

If the characters discover more layers within or without (or the layers are implied within the story), then you have a Recursive Reality.

Recursion is a phenomenon in mathematics and computer science where an equation refers to itself, allowing a finite function to represent an infinite set of objects. In physical terms, it is similar in structure to Russian Matryoshka dolls, which are designed to nest one inside the other.

The basic types:
 * The "Russian Doll World" - the worlds are physically inside one another. The most common way to travel between them is changing size. This dates back to the sci-fi pulps of the 1930s, even though the atomic model that likely inspired this trope (where electrons orbited the nucleus like planets around a sun) had been superseded as early as 1925.
 * The Nested Story - One of the oldest examples is The Arabian Nights. Scheherazade tells stories of people who tell stories about people who tell stories, and so on. This is basically a Story Within a Story or Framing Device, taken Up to Eleven. (Layers deep, that is.)
 * The Recursive Simulacrum - Building a ship in a bottle, on a ship in a bottle, basically. Someone creates an artificial world, be it a computer simulation, virtual reality, pocket universe or a miniature planet. Then someone in that world creates another simulacrum. Bonus points if an inhabitant of the last simulacrum builds another one, or the original creator's world turns out to be a model itself. Game Within a Game is a subtrope.
 * The Dream Within a Dream - A character dreams of another world, is put into a Lotus Eater Machine or starts hallucinating another life, and to emphasize the drama of the situation, the character's confusion and/or the depths of their madness, the character is pushed into a layer within or thinks they have escaped into the real world, only to find they are simply in an outer layer of the dream.
 * Transfictionality - Suppose Recursive Canon (a copy of the work itself, or a related work by the same author) shows up within the work. Then it turns out to be real, because the author of the Story Within a Story (who may or may not be the author of the actual work) is, in fact, God of his own sub-created universe. May result in Fridge Horror (or regular horror if it's addressed by the plot) if the in-story author has a Creator Breakdown. See also Rage Against the Author.

For extra headache-inducing potential, a creator might mix and match:
 * Stable Fictional Loop - Similar to a Stable Time Loop but with narration instead of time travel, this can take any of the above forms and turn it into a paradox, such as a pair of Alternate Universes that reference each other through recursive fiction, usually with paradoxical event flags that prevent you from determining which version of the story is the "outer" story, or which is the "real" story. Compare Trapped in TV Land.
 * Turtles All the Way Down - It's an infinite regress; there is no "reality" except in the mind of one character / God / the author. No matter how far up or down you go, you can't get out. Perhaps they Ascended to A Higher Plane of Existence or they're in a Dying Dream. Perhaps they're simply insane. If lucky, it's a Multi User Shared Hallucination, not a Solipsistic Nightmare. (The name comes from a famous "argument" for the Turtle Island cosmology as an explanation for gravity.)
 * Single reality - There is only one world, that is somehow enclosed inside itself. Possibly in several instances.

A similar phenomenon in art and graphic design is the Droste effect, where a picture includes a smaller copy of itself, that copy has a smaller copy of itself, and so on.

Recursive Canon is a specific subtrope where the work postulates its own existence in-story, or a fictional version of the author also exists in-story (allowing the characters to criticize it or the author or change it, of course.) Compare Mutually Fictional.

Not to be confused with Literary Agent Hypothesis, where the work postulates its own existence in real life, or the existence of a fictional author in real life (as "researched" by the real author, of course.) Compare Daydream Believer, Mythopoeia.

Compare with most Otherworld Tropes, particularly All the Myriad Ways, where the importance of all these alternates is downplayed by the assertion of a "real world", Matrix Hypothesis (also known as Recursive Reality), and Up the Real Rabbit Hole, where the "prime" level of existence is called into question. The latter is often paired with Recursive Reality for its headache-inducing potential. See also Daydream Believer, Welcome to The Real World.

Note that there has to be more than two layers shown or implied, or a path inward must paradoxically lead to the outer world (which is closer to an actual recursive equation.) Otherwise it likely falls under one of the simpler Otherworld Tropes. Shrinking into a subatomic world, for instance, does not count as a Recursive Reality unless a character can shrink further and find an even smaller world within, or somehow end up back where they started.

Also, try to keep in mind the MST3K Mantra while reading any of the examples. Believe us, it's just not worth it to lose your sanity to these.

Spoileriffic trope, as the layering is usually a major plot twist.

Comic Books

 * The Marvel Vs. DC crossover and the Amalgam Universe that resulted was explained by setting Marvel and DC continuities (each with their own fiction, past, present and future, parallel dimensions and alternate timelines) in discrete multiverses created by entities called "The Brothers". Those guys live in the "Omniverse", which supposedly contains every real and fictional universe ever.
 * Hasse's He Who Shrank inspired a number of similar comic book stories: Lost In The Microcosm (originally printed in the EC series Weird Science #12, 1950), The World Beyond (Strange Tales #32, 1954) and I Shrunk Away to Nothing! (Journey Into Mystery #56, 1960), the latter two published by Atlas, the predecessor to Marvel Comics.
 * A short Darkwing Duck comic published in an issue of Disney Adventures (titled "Cogito Ergo Something") has Launchpad holding up a dandelion and positing the existence of countless Recursive Realities to Darkwing. Sure enough, the perspective changes, and we see another world inside the dandelion seed where an alien Launchpad is presumably saying the same thing to an alien Darkwing about an alien flower. Then the perspective changes to inside the alien flower, and we see the "normal" world again (inside the inside), where Darkwing promptly blows the whole idea off as nonsense and blows the dandelion seeds to the wind.
 * Marvel's Microverse is actually a subversion of the Russian Doll World - originally it was treated as one of many microscopic universes, but it was retconned to Another Dimension accessed by shrinking so far that one crosses the Pym Barrier. Also, once in the Microverse, characters cannot shrink any further.
 * In one tale, the cosmic entity Kubik was educating the younger cosmic entity Kosmos on the structure of the universe by growing from the mortal level through the galactic, eventually becoming larger than the universe, than larger than the trans-cosmic realm where universes exist ... only to pop up to the level of quarks, and growing up past the atomic level back to the mortal realm. As Kubik said it; "The center of the universe is wherever you happen to be at the moment."
 * Grant Morrison's The Filth shows several microcosm-style environments (including a city contained by an enormous ship and a miniature world populated by "I-Life"). The Hand's base, The Crack, is implied to be created to harvest the   The Crack, in turn, is home to the Paperverse, the fictional reality that The Hand mines for exotic technology.
 * Warren Ellis's Planetary sums it up best itself:
 * "This is the shape of reality. A theoretical snowflake existing in 193,833 dimensional space. The snowflake rotates. Each element of the snowflake rotates. Each rotation describes an entirely new universe. The total number of rotations are equal to the number of atoms making up the Earth. Each rotation makes a new Earth. This is the multiverse."
 * Said by someone who developed a quantum computer in 1945 which uses the shape of the multiverse to compute and create situations upon their Earth to solve problems. That's right: using the entire multiverse to effect changes upon one single world within it. So fractal it hurts.
 * All-Star Superman shows Superman, wondering how the world will function without him, creating a miniature Earth in a miniature universe. It grows relatively quickly, and the last panel of the issue shows someone drawing a comic-book character, declaring "This time, I'll change everything..." The character is Superman - it's our world, the man doing the drawing is Joe Shuster, and we have a loop.
 * The ending to Irredeemable is basically this:.
 * This strip from cartoonist Quino.

Film

 * The MacGuffin that draws Edgar Bug to Earth in the first Men in Black film is . The final scene reveals that
 * Men in Black II pulls a similar gag by showing a world inside a locker where K's watch is a symbol of worship, then at the end, K shows J that their world is also simply inside a larger locker (doesn't work quite as well as the first film, due to Fridge Logic).
 * An alternate ending has J going on vacation and ending up on the world inside the locker and the size of its inhabitance, implying some sort of change in size when you go through the locker door, or that the lockers are more of a Portal Network.
 * Todd Haynes' Bob Dylan biopic I'm Not There uses a form of this to analyze Dylan's ever-changing personality by having him played by five different actors (and one actress), each of whom's story is depicted in a different genre and visual style. Christian Bale's Bob Dylan expy has his story done in documentary style, and his character was played by Heath Ledger's Dylan in an in-universe Biopic. An image of a young Bale appears in a high school yearbook of the Cate Blanchett Dylan, implying that her story is another movie-within-a-movie (or perhaps a drug-induced hallucination), supported by the fact that her segment is shot in the style of Fellini's 8 1/2. Richard Gere, playing Billy the Kid, is antagonized by Pat Garrett, played by the same actor who plays a reporter who harasses Blanchett, implying that the entire story take place within her mind. And that's only four of them... Several of the stories seem to exist within the minds of one Dylan or parallel to the events of another.
 * Rainer Werner Fassbinder adapted Daniel F. Galouye's 1964 novel Simulacron-3 into the german movie Welt Am Draht (aka World On A Wire) The protagonist maintains a computer simulation of a whole city. After strange events happening in the real world it is revealed that . The movie was released in 1973, so is possibly the first film to adapt this trope.
 * Simulacron-3 was also adapted into the 1999 American film, The Thirteenth Floor.
 * Charlie Kaufman's directorial debut, Synecdoche New York, is about a playwright who, as part of his new play, creates a life-size model of New York in a warehouse filled with thousands of actors. This model contains a warehouse, which contains another life-size model of New York, which contains another warehouse...
 * Kaufman's earlier screenplay, Adaptation, is the result of his struggle to write an adaptation of The Orchid Thief, and is about the story of a screenwriter character named Charlie Kaufman, who struggles to write an adaptation of a novel titled The Orchid Thief. The fictional Charlie gives up, too, and writes a screenplay titled Adaptation, which is about, well, you can probably guess...
 * In the movie Spaceballs, the villains actually put in a video of their own movie, and go to the scene where they are watching it, seeing an infinite number of themselves watching themselves.
 * This is the central point of eXistenZ - the protagonists are confused about how many levels of virtual reality Game Within A Game there are, and what they're supposed to do to win.
 * Inception has dreams within dreams within dreams (and so on) with time slowing down exponentially with depth, allowing someone to spend decades inside dream worlds.
 * The Fountain is a film about a man hunting for the Fountain of Youth Who Wants to Live Forever?. It features the same two characters in three time periods. Given that, you assume they succeed, and Complications Ensue when the girl gets sick and threatens to die on him due to Phlebotinum Failure. But no: the past timeframe is the plot of a book about Tom as a conquistador, told by the dying present day wife, and Tom's character Ascends To A Higher Plane Of Existence in the future timeframe, where he bodily intervenes in the plot of the uncompleted book. Meanwhile, the present Tom does find the Tree of Life,, and the Tree in question is dying, so he plants another one  where she predicts it will resurrect her as a tree...at the end of the story, the conquistador succeeds in living forever when he stabs the bark of the tree and  . He drops his ring, a a gift from the Spanish Queen, which the future Tom picks up. It turns out to be the wedding ring that the present Tom had lost.
 * In the movie Last Action Hero, in Jack Slater's universe there are movies where Sylvester Stallone takes up Arnold Schwarzeneggar's roles. This is a movie within a movie within a movie. The Nostalgia Critic (a fictional character) reviews the whole thing, adding another layer.
 * Horton Hears a Who! is about an elephant who hears voices from a tiny town called Who-ville, built on a dust mite. In the animated version, there's a Stinger where the mayor of Who-ville hears voices coming from a Who-scaled dust mite...

Fine Art

 * This lithograph by M. C. Escher depicts a man in an art gallery looking at a picture of a harbour. As the eye follows the scene clockwise the harbour expands into a city, which expands into a detail of a building containing a gallery full of Escher's drawings, which turns out to be the gallery in which the man is standing.
 * There was a documentary about an attempt to figure out what would be in the white spot in the middle of the picture. The answer turned out to be the picture itself, shrunk and rotated. Of course that image would still have a white spot...

Literature
"If untold buddha-lands are reduced to atoms, In one atom are untold lands, And as in one, So in each. The atoms to which these buddha-lands are reduced in an instant are unspeakable, And so are the atoms of continuous reduction moment to moment Going on for untold eons; These atoms contain lands unspeakably many, And the atoms in these lands are even harder to tell of."
 * Indra's Net (Sanskrit: Indrajāla): Perhaps the oldest extant example of this concept is to be found in the Mahayana Buddhist text "Avatamsaka_Sutra", circa 3rd century:

"The Mathemagician stopped what he was doing and explained simply, "Why, in a box that's so small you can't see it - and that's kept in a drawer that's so small you can't see it, in a dresser that's so small you can't see it, in a house that's so small you can't see it, on a street that's so small you can't see it, in a city that's so small you can't see it, which is part of a country that's so small you can't see it, in a world that's so small you can't see it." Then he sat down, fanned himself with a handkerchief, and continued. "Then, of course, we keep the whole thing in another box that's so small you can't see it - and, if you follow me, I'll show you where to find it.""
 * The Phantom Tollbooth has the location of the number Infinity.

"I felt, on the last page, that my narration was a symbol of the man I was as I wrote it and that, in order to compose that narration, I had to be that man and, in order to be that man, I had to compose that narration, and so on to infinity."
 * Older Than Print: The Arabian Nights is the Trope Maker for the metafictional version - For example, Scheherazade tells the story of The Fisherman and the Genie, where the fisherman keeps the genie from killing him by telling it The Tale of the Vizier and the Sage Duban, during which the evil vizier tells his king The Tale of the Husband and the Parrot.
 * Spoofed by Hungarian writer Frigyes Karinthy who takes it to ridiculous levels.
 * The 19th century novel The Manuscript Found in Saragossa has a similar structure - Alphonse van Worden meets, imagines, or reads about a number of colorful characters in intertwining stories, in the course of his journey to Madrid.
 * One of the simpler examples, the Total Perspective Vortex that Zaphod confronts in Douglas Adams' The Restaurant At The End Of The Universe is a within "the real thing".
 * Brian Aldiss' Report on Probability A presents a circular sequence of worlds. Mrs Mary is being watched by her three servants, G, S and C, who are being watched by some aliens from a parallel universe, who are being watched by scientists observing a rift in reality on the top of a hill, who are being watched by... until we come to the observers in the "outermost" reality, who turn out to be the figures in a painting in the cafe that G, S and C frequent.
 * In Piers Anthony's Xanth series, Princess Ida has a tiny moon the size of a baseball that orbits around her. The moon contains a whole world with its own Ida, and that Ida has a moon with a different world on it, but that moon also has an Ida, who has a moon and so on and so on and so on. Faun And Games was about exploring these moons, and the main character goes through at least six layers.
 * Actually he only went down three layers, and learned of a fourth.
 * In the following book, and in many others beyond, they learn of more and more moons in the line, though past Fractal (#16) the sequence gets murky. In a recent book, Air Apparent, it turns out there is in fact a finite number of moons, and it is possible to cycle through them all the way to Earth, and now it is possible to go back to Xanth in the same fashion.
 * House of Leaves is about Johnny Truant, who's editing Zampanó's manuscript about a documentary made by Will Navidson. Neither the documentary nor Will Navidson exist in Johnny's universe, and they may or may not exist in Zampanó's universe. This is the most simplified description possible.
 * Philip K. Dick's novel Ubik: The Stinger indicates that And Here We Go Again...
 * Toyed with in Diane Duane's The Book of Night with Moon. There's a Prime Reality, but it certainly isn't our Earth, and there's nothing better or worse about a given layer. Those layers closer to the prime reality have rippling effects on the surrounding realities, especially those further down the line, though. Taking a chunk of the biggest Russian doll is bad. Smudging the paint on the smallest might be universe-destroying for the bigger dolls.
 * Greg Egan's Diaspora is a Recursive Reality, beginning with the computer network the posthuman protagonists live in and ending in a more or less endless number of non-euclidean universes.
 * In Jasper Fforde's Thursday Next novels, all the worlds of literature exist in a parallel multiverse called the Bookworld. First Among Sequels features two fictional versions of Thursday herself. If you think about it the books they come from must contain another version of the Bookworld itself.
 * At the end, Thursday observes the remaking of the first Thursday Next book. The "on-stage" part is cut-and-pasted from The Eyre Affair.
 * And, of course, the "Outworld" - the real world that Thursday comes from - is a fictional world written by Jasper Fforde. She doesn't think so, but occasionally something happens to make her wonder.
 * In Jostein Gaarder's Sofie's World, who knows how many more layers there might be...?
 * One of the oldest Science Fiction examples is He Who Shrank by Henry Hasse, originally printed in 1936 in Amazing Stories. The protagonist is injected with a serum that causes him to shrink smaller than an atom, where he discovers that every atom is a solar system, with a nucleus for a sun and electrons that orbit like planets. He shrinks through several universes until he lands on our world, and tells his story to a writer who unsuccessfully tries to sell the story to a newspaper as nonfiction.
 * Also notable because Science Marched On eleven years before the story saw print - quantum mechanics began to supersede the Bohr-Sommerfeld orbital model as early as 1925, although the Bohr model is still taught today because 1. it accurately predicts the behavior of hydrogen atoms and 2. ease of depiction (subsequent models are heavy on equations and don't actually look like anything.)
 * One of the Choose Your Own Adventure books did that too, but with quarks as universes.
 * I don't know, Timmy, being God is a big responsibility.
 * Stephen King's first Dark Tower book implies that Roland's universe is a Recursive Reality, specifically an atom in a blade of grass in our own universe. Later books muddle this somewhat.
 * In later books, you find out it also counts as Transfictionality and Recursive Canon. So the universe is in a blade of grass in another universe, written by the author.
 * More specifically, the Dark Tower setting is more like a mobius strip of recursion, wherein our world simultaneously contains and is contained within Roland's universe, each being both lesser and greater than the other. The Dark Tower tends to be somewhat insanely metaphysical.
 * The atom-in-a-blade-of-grass thing was never established to be definitely true; more the the Man in Black was just asking Roland to ponder all the infinite possibilities of creation. The whole thing was just a diversion to fuck with Roland's head and get him good and confused while the Man in Black slipped away unnoticed.
 * But the Dark Tower canonically manifests in our world (or a similar parallel universe) as a single, perfect rose on an empty lot in Manhattan.
 * The Cyberiad: Fables for a Cybernetic Age (1967) by Stanislaw Lem has a robotic prince trapped in recursive virtual dreams by his Evil Chancellor. Once the prince realises what happened, he panics, and desperately tries to wake up "for real" - and at one point he does, but, thinking in his panic that he is still dreaming, keeps trying, thus falling back into endless recursive dreams forever.
 * This happens in a story within a story.
 * In one of the Lem's The Star Diaries story, Ijon Tichy visits the scientist, professor Corcoran, who build numbers of electron brains. Those electron braines closed in the chests have consciousness and they are thinking that they are real people. Chests are wired to the device which sends electric signals to those brains senses imitating perception of real world. Those brains have no clue about their real situation. Except one, who is called by Corcoran 'his world lunatic'. Because of some world imperfections (such as Deja vu or theory of Seriality), this brain suspected that it is not real and everything is just illusion which is served to him by someone or something. At the end of conversation, professor Corcoran admits, that he is also suspecting that he is not real and surrounded by phantoms, products of false signals sended to his senses and that it is probable that even creator of this world is also a chest in someone laboratory, and so on and on...
 * In CS Lewis' The Chronicles of Narnia, all universes are connected to the Wood Between The Worlds, a forest dotted by pools. Each pool serves as a portal to a universe.
 * In the John Crowley novel Little, Big, the world of the Fae is smaller than the human world and exists in cracks and crevices of the latter. By the time a slow-motion End of an Age comes around,  The further in you go, the bigger it gets.
 * In the Science of Discworld novels, the wizards create a "model universe" they christen Roundworld. Roundworld is, of course, our world - which implies that eventually Roundworld will contain an author named Terry Pratchett who will write stories about a Discworld in which wizards create a Roundworld, etc.
 * At the end of the first Science of Discworld, Hex actually states (er, writes) definitively that recursion has in fact occurred.
 * Another Discworld example, this time from the main series. In Sourcery, the main characters have to travel across the Circle Sea, and do so in the djinn's lamp being carried by one of the characters, which they still have in their hands inside the lamp. This only works because one of them is carrying the lamp and is moving... because they are inside the lamp being carried. It stops working when the universe realises what's going on, so they are told not to think it through, leading to one of them doing exactly that...
 * Not exactly "literature", but the Australian picture book Puzzle Worlds is based on this. A gaggle of hapless airline passengers find themselves in a world inside a well in a town on a flea on a zoo animal... and various nested worlds inside that.
 * In a story in Bigot Hall by Steve Aylett, the protagonist and his friend go out to a small island in the grounds of his home. The first thing they find is a tiny fence, when they tread on it, and then a model of the hall, including a little lake with another, even smaller model of the hall, which has a tiny lake with tiny model...and at this point they freak out, fearing that if look up they'll see giants above them. His father finds them later (hiding under a tarpaulin), and says he knew they were out out on the island when he saw that part of the fence had been flattened.
 * Flatland contains Lineland inside it, which contains Pointland inside it. It is itself contained in Spaceland, which may be contained in a higher dimension. So, while there are only 2 recursions inward, there may be an infinite amount outward.
 * There is a story called "Fessenden's Worlds" by Edmond Hamilton, where a scientist creates a miniature galaxy to experiment upon. After he's killed (along with the galaxy), a friend of his, who saw it all, keeps thinking "is there a Fessenden out there"?
 * A Soviet story "Engineer Alexeev's Mistake" is about a scientist who created a tiny galaxy orbiting Earth. When some time later he decides to shut it down, it turns out that due to time passing differently there, the galaxy has already developed an advanced civilization (with a communistic government, naturally), and managed to retaliate by putting the scientist in stasis.
 * Book of Amber uses this, with Amber (and, it's implied, one location in that world) being the ultimate physical manifestation of an ordered reality. All other worlds are shadows of Amber, or shadows of shadows, or so on recursively... all the way down to pure chaos, near which the worlds are so volatile you can often just walk from one to the next.
 * Cloud Atlas is a series of nested stories, told in different stories, through different mediums (a log book, a screenplay, a spoken story, etc) which abruptly end part way through as the next story begins. Each of the main characters will at some point actually find the previous story, get to the point where it was cut off, and for one reason or another be unable to finish it either. Only the "center" story is unbroken, and as it finishes the others are picked up again and one by one finished.
 * Roald Dahl uses this trope a few times, most notably in The Wonderful Story of Henry Sugar.
 * Lawrence Miles's Doctor Who Expanded Universe novels contain frequent references to the "bottle universes". The intent appears to be that the Virgin New Adventures universe exists in a bottle in the Eighth Doctor Adventures universe ... and vice versa. Mind Screwy enough on its own, other authors (who believed both book series were in continuity with each other) muddled things even further, eventually establishing it was a Klein bottle, and the universe was inside itself.
 * Subverted in Jorge Luis Borges short story  "Averroe's Search" : In the last page, Borges realizes that he has broke the Stable Fictional Loop and incurred in an Ontological Paradox


 * In The Enduring Flame Trilogy, Tiercel proposes that the worlds are each nested inside the other like a puzzle box. When "lined up" properly, something can move from one world to the other.
 * The Dresden Files: At one point, Harry made a scale replica of Chicago, with a powerful spell on it. When he uses it, he "enters" the model, and is able to move around it. And through it, he can observe things happening in the real Chicago. One unnerving aspect of the spell is that if he looks up at the sky, he sees the interior of his own basement, and a giant size version of himself concentrating intently on the spell.
 * The plot of the Bernice Summerfield novel Dead Romance uses this trope for some hardcore Mind Screwery; the protagonist discovers that she is from a Universe-in-a-bottle created by the Time Lords, and the reason her (and by extension, our) universe is so mundane is that the Time Lords didn't have enough material handy to recreate all the crazy aliens that humanity in the "proper" universe seems to run into every week. A visitor from the outside universe is astounded that the Pyramids were actually built by humans instead of Ancient Astronauts, for example.
 * A very wide variety of examples can be found in Douglas Hofstadter's book Gödel, Escher, Bach: an Eternal Golden Braid, in which recursion and self-reference, particularly applied to mathematical proof about the nature of mathematical proof, are major themes.

Live Action TV
"Doctor: Recursive occlusion! Someone's manipulating Castrovalva! We're caught in a space-time trap!"
 * The Star Trek: The Next Generation episode "Ship In A Bottle", where the Professor Moriarty created on the holodeck to outwit Data is discovered to be sentient and demands that the Enterprise crew work to transfer him into their world. Data later discovers that As if that wasn't headache inducing enough, Picard wonders aloud whether the "real world" could be yet another simulation, which prompts Barclay to test his hypothesis.
 * His exact words are, "All this might just be an elaborate simulation running inside a little device sitting on someone's table." After he leaves the room, Barclay nervously says, "Computer, end program." The episode ends there.
 * In Mork and Mindy, Mork once shrank down to microscopic size and ended up in an alternate world.
 * The Doctor Who serial "Castrovalva" features a variation on this, where the entire town (a town called Castrovalva) had been warped in on itself. One of the cliff-hangers had a hilarious line from the Fifth Doctor.


 * The deliberately over-the-top delivery of that line was lampshaded in the "Castrovalva" commentary where Davison described it as "end of episode acting".

"Shirley: I'm reacting the way the world does to movies about making movies about making movies! I mean come on, Charlie Kaufman, some of us have work in the morning, damn!"
 * The entire premise of the Doctor Who episode "Amy's Choice" is a choice between two possible realities in which they keep falling asleep and "dreaming" of the other world, in which they are entirely convinced they are in the "real world" again.
 * Then there was the time the TARDIS ended up inside the TARDIS.
 * In the Buffy the Vampire Slayer episode "Normal Again" Buffy is poisoned by a demon that makes her hallucinate that she's in a mental institution, and has been hallucinating her life as a Slayer in Sunnydale.
 * That presumes that Buffy would have to be in every scene, but in Normal Again she not only goes unconscious in the first few minutes but the asylum continues to exist when she is not present. It could simply be that Buffy is the grand creator of the entire Whedonverse, which is not a stretch considering we only see one-hour glimpses into her life at any one time and there is magic in the Whedonverse than can create a lifetime of false memories.  Anyway, due to some intense backlash, Word of God is unlikely to be trustworthy at this point.
 * OR maybe there are two realities - one where Buffy's crazy and the other where she's the slayer - that just crossed paths at that point in the timeline before splitting again.
 * America's Funniest Home Videos had a clip of their dog reacting to the show. Later, a different family sent in a clip of their dog reacting to that dog reacting to AFV. Even later, the family that sent in the first clip sent in a clip of their dog reacting to the other dog reacting to itself reacting to AFV.
 * Despite multiple concrete examples of crossovers that put Victorious, Drake and Josh, iCarly and Zoey 101 in the same Nick Verse, Victorious as part of one episode refers to Drake and Josh as a TV show.
 * Abed tries to do this via a film project in Community. It doesn't work.


 * In Cosmos, Carl Sagan speculates that our universe could be the equivalent of a subatomic particle inside a "superuniverse".

Music

 * The cover of the Pink Floyd album Ummagumma is a photo in which a variation on the same photo is hanging on the wall, which itself contains a variation on the photo and so on.
 * Michel Gondry's music video of Björk's song Bachelorette, in which the protagonist finds a book buried in a forest. The book starts write itself, gets made into a stage play and movie about how the book is found, up to the point where the play depicts the play being staged, leading to a play within the play, a play within a play within a play, etc. In the end,

Newspaper Comics

 * In a reversal of the He Who Shrank scenario, Calvin once grew to the size of a galaxy and finds a door that leads back to his own room.
 * A Pearls Before Swine comic strip featured Pig meeting Atlas who held the Earth on his shoulders. Pig then points to the part of the Earth where he is, and his giant hand comes down and pokes his eye.
 * Dilbert had to deal with a guy so cocky, he thought he was the one holding up the infinite turtles.

Tabletop Games

 * The 1st Edition Dungeons and Dragons modules I6: Ravenloft and I10: The House on Gryphon Hill, could be played either as stand-alone adventures, as an adventure and its sequal, or as interlocked adventures in which PCs who retired for the night in one module would wake up in the other, and vice versa. This last option could be played as a recurring All Just a Dream, as a recursive Dream Within a Dream, or as the result of genuine shifts between realities.
 * One campaign for The Dark Eye featured a pocket dimension containing an archipelago on whose islands certain legends were true. One suggested subplot depended on one character dying there; their soul would be transported to, and be able to have encounters in, another dimension while the rest of the group was supposed to find a way to bring them back. (This is not the norm in this game system; mostly, dead means dead.) It was mentioned that if the soul was swallowed by a certain kind of monster, it would be thrown into a realm even further removed, from which they could not be brought back.
 * The farming board game Agricola features several different "Room" tiles, in of which a game of Agricola is being played (a few posts down here).
 * One of the Activity cards in the card game Chez Geek is a "Stupid Card Game", and the art for the card is a bunch of geeks playing a game of... Chez Geek.
 * Malfeas in Exalted. When the Exalted overthrew the Primordials, they needed some way to imprison titanic beings the size of mountains and planets somewhere far away from Creation. Their solution: turn them all inside-out; imprison Malfeas, the Demon City inside the body of Cecylene, the Endless Desert; then imprison all the other Primordials, including Cecylene, inside the body of Malfeas; finally, boot them out of Creation into a separate dimension. Even this was considered too insecure for one Primordial, who ended up imprisoned inside his own wings. Understandably, they're a bit miffed.
 * One adventure for the appropriately-named Over the Edge suggests that the gamemaster swipe a small item off the table that the players will miss but not worry too much about. The object then shows up in the game world and proves to not quite follow the laws of physics. This can potentially escalate to the player characters arguing with the players.

Theatre

 * The final scenes of the play Stones in His Pockets concern the main characters trying to get producers to look at a script they wrote, called "Stones in His Pockets."
 * [title of show] is a musical about two guys writing a musical about two guys writing a musical.
 * "A, D, D, D, D, F-sharp, A... will be the first notes of our show..."
 * The Romanian play, Jonah is about a man trying to cut himself out of the stomach of a fish, only to find that said fish has been swallowed by another fish. In the end, he finally realises that the whole world is made of fishes, and he just wasted his entire life trying to escape, instead of living normally.

Troping Wikis

 * At the amazingly fast rate we're adding tropes to this and The Other Tropes Wiki (as well as some other stuff), they will soon contain all the tropes that could possibly exist (and those that can't either). But if we put all the tropes that (don't) exist together, we are, in fact, describing the universe (and, indeed, all possible universes that can and cannot exist), so effectively, troping sites will contain all the universe within them, including themselves! Which, in turn, will contain themselves within them, and they will also contain themselves within it, ad infinitum. How's that for a Mind Screw?
 * Of course in actual fact it's a bit more of a moebius strip than universe-contained-universe: You just get through the entire site and the last page link you back to the first. It only really counts if pages start referencing the different layers of meta-reality that would be in play, otherwise Occam's Razor suggests that since we can only see one universe, there is no logic in assuming there's a second one.
 * If you click on Transfictionality, Recursive Simulacrum, Matrix Hypothesis, Russian Doll World, or Turtles All the Way Down, (all of which are found on this page), they lead you back to this same page.

Video Games

 * During the board game battle between the two Bonapartes in Psychonauts, you can shrink down and travel on an enlarged version of the board game. This allows you to look inside the windows of the prop houses on the board where, in one house, you can find the two Bonapartes playing the board game!
 * In Fallout 3, this is the basis of the Church of Atom, a cult that worships the "creative" power of nuclear bombs - they believe that every atom is an entire universe and the splitting of atoms equals the birth of whole new universes and, well, just don't let them near your nukes.
 * Nobody ever explain fusion bombs to these people. It might spark a holy war.
 * At various points throughout the Pokémon games, the player will encounter NPCs who themselves are playing Pokémon. Presumably, these games also contain NPCs playing Pokémon, and so on.
 * In the Sierra point-and-click game Torin's Passage, the worlds are all physically nested within each other, and accessible through warp gates called Phenocrysts. The worlds all have their own atmosphere and sun except The Null Void, so it's not clear if the worlds exist within the same dimension.
 * In Kingdom of Loathing, you can shrink down and fight scabies (skin mites) on your own leg.
 * The Crimbo 2010 event lets you work in an office that gradually increases your Boredom. Get it too high and you might face the Tome of Tropes, get it to 100% and your character starts playing the Best Game Ever.
 * External Gazer, one of the "Snake Tales" included as a bonus in Metal Gear Solid 2: Sons of Liberty: Substance, revolves around the use of the virtual reality system that is the in-universe explanation of the "VR Missions". It turns out that not only does it work by, it's also possible for the "simulations" to be nested. Plus, they're nested such that . It pretty much bends the fourth wall into the shape of a Klein bottle.
 * In Sim City 2000, one of the articles in the in-game newspaper is about schoolchildren learning about city management by playing a Sim City-like game. One of the students interviewed for the article wonders if they're actually just characters in a game like the one they played...
 * The Stinger of Super Mario Galaxy 2 (which is shown after defeating Bowser in the final level for the second time), actually reveals that the game's events are all part of a storybook Rosalina was reading to the Lumas. While Mario and Yoshi are both flying through space rescuing Peach and the Power Stars from Bowser.
 * And then Rosalina writes herself into her own story about the game where she gives Mario the final Power Star.
 * In Minecraft there are people who have built working computers in the game itself. It has been speculated how long it will take untill we're playing minecraft in mine craft.
 * It begins.
 * In Assassin's Creed Revelations, Desmond is in the Animus living Ezio's memories, who uses the Masyaf Keys to live Altair's memories.
 * Part of the plot of Imperishable Night, the eighth game in the Touhou series. In order to avoid discovery emissaries from the Moon, lunarian refugee Eirin Yagokoro hides the Earth in a magic pot with a fake sky on the inside. She then hides the pot in her home of Eientei. Which is on Earth. Which is hidden in the magic pot.

Web Comics

 * The page pic is from a The Perry Bible Fellowship strip in which an astronaut somehow lands on his own helmet; when he takes it off he can see a miniature figure of himself standing on it holding a miniature helmet with an even smaller figure of himself standing on it holding...and to make his day even worse, his bald spot is spreading.
 * Darths and Droids has no film version of Star Wars in its world, with the plots of the movies used for a Tabletop Game instead. In that world, however, there is a webcomic about a world that has no Harry Potter movies, with the plots of those used for a Tabletop Game. The layering goes down and down and down, with another movie added every 50 strips.
 * Getting very meta with this one based on Inception.
 * This Xkcd.
 * xkcd has actually played with this a few times.
 * In Homestuck, the Battlefield, Skaia, is contained in the King's scepter. Said king is fighting on the Battlefield. And there are two kings.
 * Also, one of the characters in the previous universe picked up the game disc for the second universe's session. It appeared to be a record, so when Terezi tried playing it in a gramophone, it ended up being scratched, leading to visual glitches in the comic, rendering it "unplayable." It's up to Doc Scratch to fix the scratch, and he promises do so before the comic's Act 6, when The Scratch occurs. Oh, and don't forget when Andrew's out-of-continuity avatar promised to interfere directly in the plot one time. Is this a new trope, the Reality Wality Ball? We already had the time version what with all the past/future and time-uncoordinated two-universe conversations, and that whole Midnight Crew Intermission.
 * Every single universe is apparently a giant frog.
 * Penny Arcade in "Ad Infinitum" (which of course is also metahumour).
 * Penny Arcade in "Ad Infinitum" (which of course is also metahumour).
 * Penny Arcade in "Ad Infinitum" (which of course is also metahumour).

Web Original

 * The Nostalgia Critic once reviewed the movie Last Action Hero. He is a fictional character who is watching a movie featuring a fictional character who watches a movie about a fictional character who has movies featuring fictional characters portrayed by Arnold Schwarzenegger.
 * The ending of Red vs. Blue: Revelation leaves room for the interpretation that the entirety of the Recollection trilogy is Burnie Burns stated in an interview that the setting of Blood Gulch Chronicles was real, but deliberately left the rest open to debate.
 * From Stuart Ashen: this wall in a pub (0:26 may startle you).

Western Animation
"Homer: "...Wwwwoooow.""
 * Adventure Time: the "The Real You" episode.
 * Animaniacs: the song "Yakko's Universe" had the entire universe turn out to be inside Yakko Warner's snowglobe twice.
 * Futurama: In "The Farnsworth Parabox" our heroes end up owning a box that contains the universe that contains them.
 * In another episode, Amy plays a game of virtual virtual skeeball - a simulation of a game of virtual skeeball.
 * In yet another episode, Leela experiences the Dream Within A Dream type. She slowly realizes she's in a dream (or going insane) and keeps trying to escape only to end up in more bizarre situations. She meets Fry each time who tells her she needs to "wake up". Turns out
 * I Am Weasel: an episode [tba] revolves around Weasel, Baboon and Red Guy trying to find out where everybody in the world has gone to, leaving every public place empty. It turns out everybody is home, watching I Am Weasel. And yes, it DID in fact include a shot of Weasel in front of a TV showing him in front of a TV showing him in front of a TV showing him... To be honest though, this wasn't even one of the weirdest episodes.
 * Johnny Test has an episode similar to "He Who Shrank" - Johnny shrinks to smaller than a quark, and it turns out that each quark is an entire universe.
 * Rick and Morty: a 3-deep Recursive Simulacrum forms the plot in the episode "The Rick's Must Be Crazy". Rick's space craft's battery utilises a "microverse" to power it. In this universe, the inhabitants perform a repetitive action to generate energy in a ruse to provide power to Rick's battery (which they do not know about). A scientist within Rick's "microverse" develops his own miniature cosmos, which he calls the "miniverse", employing similar slave labour to generate energy for him (which Morty berates Rick for rationalising). Finally, there is a scientist within this cosmos working on his own "teenyverse".
 * This trope is initially played straight and then for laughs, as Rick thinks his "microverse" is superior and mocks the silly sounding names "miniverse"/"teenyverse" (which are unwitting parodies of his own "microverse").
 * Rick ends up in a stand off in an amusing Inception meets Matrix scenario.
 * South Park uses the fourth type for 1 Episode. In the end, it turns out that Stan has emotional problems, so he, Kyle, Cartman, and Kenny (who didn't technically die this time) go for ice cream. The End.
 * The Killing Of An Egg: the short film by Paul Driessen. A man hears a voice coming from the soft-boiled egg he is cracking and maliciously crushes it. He then hears knocking outside his house, and finds that he is now the one being crushed.
 * The Simpsons: a Couch Gag begins with a reverse Astronomic Zoom from the Simpsons' couch to outer space, revealing it to be an atom in one of Homer's hairs.


 * Teen Titans: an episode [tba] had the characters being imprisoned by Mumbo in his magic hat. Cyborg points out that Mumbo, appearing in the world inside the hat, is still wearing his hat. Which everyone is still inside. Including Mumbo. And his hat.
 * One Kids WB ad for the show has Robin and Starfire sitting on the couch in front of the TV. Starfire asks Robin what he's watching; he says he's watching Teen Titans. Zoom out to show a recursive image and Starfire asking Robin the same question. They do this enough times to put it barely short of an Overly Long Gag, then Starfire Breaks the Fourth Wall, asking the audience what they're watching.

Real Life / Other
"Man #1: If Earth is the back of a giant turtle, then what's holding up the turtle? Man #2: Don't be a fool. It's Turtles All the Way Down!"
 * Infinite Fractal Zooms, such as Mandelbrot Sets "Bigger than the known universe!" Turn on the Mood music when watching these... Schpongle perhaps.
 * There are any number of magazine covers with a Droste Image - where somebody on the cover is holding a copy of the magazine with the cover that they're in, etc. Here's a recent example.
 * Hell, Games Magazine made a puzzle out of it.
 * Numerous commercials have used a similar effect, where a photograph in one scene expands and animates, becoming the ad's next scene. Usually, this also has a photo or other image in it, which also expands and animates...
 * Raëlians believe that our universe is a tiny particle within the body of a living creature in a much larger universe, and that all atoms in our universe also contain smaller universes similar to the one we live in.
 * Archimedes Plutonium believes (or pretends to, depending on whether you think he's an actual nut or a troll who doesn't know when to stop) that the Universe is an atom of Plutonium (and changed his name accordingly).
 * The Turtle Island cosmology is the basis for the famous often-cited "argument" / joke / thought experiment in cosmology and metaphysics known as "Turtles All The Way Down", see that other wiki for details:


 * Have two mirrors face each other and look at what you see in them.
 * Or for a hi-tech version, hook up a video camera to a monitor and point the camera at the screen.
 * Who cares. Go here. Right-click download and Save as OR you can go over here oh! Can we watch ourselves? Will it let us do that on here OH MY GOD
 * The Universe has about the size and mass of a really big black hole (which need not be very dense). It is therefore conceivable that black holes contain universes. (The border of our Universe would therefore be its event horizon.)
 * A related fact: Objects in space tend to gather into groups due to gravity, like planets around starts, whereas stars gather into clusters, clusters into galaxies, and galaxies into superclusters. Basically the only thing that isn't a group held together by gravity of its components is the universe itself. This also works in subatomic level. To what extent, we can only guess.
 * Gravity does not apply on the quantum level, and the universe isn't much of a "thing" beyond a hole where everything else is.
 * Gravity does apply on a quantum level, but it doesn't apply significantly, and the other forces typically overwhelm any influence it has.
 * Philosopher Nick Bostrom has proven that if there's ever going to be a recursive simulation of reality, then we're probably in it already.
 * This is related to the notion of Transhumanism and the "Omega Point" theory that technology and human awareness is accelerating exponentially toward an Omega Point where we will be aware of all things in existence. Somewhere a Statistician is Crying...
 * There was this animated ad years ago for something or other... anyway, there's this piano melody. And we see the pianist. Pull out, he's in a bubble, pull out, gets eaten by a fish, which is in a little boy's bathtub, which is in a house, in an apartment block, in a city, on a magazine cover, being read by an Arab on a camel, which is actually on a stamp on an envelope, being delivered by... and on and on until it's all in a little girl's toy city and that damn piano melody stops.
 * The Internet, perhaps. If nothing else, it can, and possibly should, be seen as a world within a world.
 * As seen by web archive sites, the Internet also contains (incomplete) copies of the Internet, making it partially recursive.
 * It Got Worse. These days, there are many, many social networking websites. To get into it, you typically have to sign-up. Those who don't sign-up don't see what's happening in those websites. It's thus an internet inside the internet ('sup dawg). This is a problem for search engines, who want as much information as possible from everywhere on the internet. Apparently, this "hidden web" phenomenon is disturbing enough for Google that it's criticizing Facebook for exactly that.
 * Emulators and virtual machines. VirtualBox, for instance, simulates one PC within another PC; it's great for playing with different mutually incompatible PC operating systems or for completely isolating applications in one "box" with another. In fact, it's possible to run PocketNES (a Nintendo Entertainment System emulator for Game Boy Advance) inside VisualBoyAdvance (a GBA emulator for PC) inside VirtualBox.
 * In case you're worried about the universe exploding by paradox, here's another thing to worry about: does the set of all items that do not belong in a set include the set itself?
 * It does in exactly half of all possible sets.
 * in this video someone uses the imbedded web browser in Second Life (textured to an in game laptop no less) to access a remote desktop viewer, which they use to.....log in to Second Life
 * So would that be Third Life?
 * This photo is a partcularly clever example. Look closely.
 * Google recursion.
 * The Model Village at Bourton-on-the-Water in the United Kingdom is a one-ninth scale model of the Cotswold-stone village of Bourton-on-the-Water as it existed in the 1930s; part of the model is a model of the model, which itself contains yet another, smaller model of the model of the model. And that one has a playing-card-sized area marked out with the roads and river of an even smaller model, but no buildings.  Counting the real, full-size village and the playing-card-sized one, that's five levels deep.