strange loop
absurdism – Theory that life in general is absurd
Autopoiesis – Systems concept which entails automatic reproduction and maintenance
Conundrum – Study of correct reasoning
Catch-22 – Situation in which one cannot avoid a problem because of contradictory constraints
Causal loop – Sequence of events which cause each other
Dilemma – Problem requiring a choice between equally undesirable alternatives
Euthyphro dilemma – Ethical problem on the origin of morality posed by Socrates
Grandfather paradox – Theoretical paradox resulting from time travel – Going back in time to kill one's own grandfather generates a circular contradiction
Hysteron proteron – Figure of speech reversing a natural or rational order
Irony – Rhetorical device and literary technique
Klein bottle – Non-orientable mathematical surface
Mise en abyme – Technique of placing a copy of an image within itself, or a story within a story
Meno – Dialogue by Plato - Paradox: One must already possess any given piece of knowledge, otherwise it could not be recognized when supposedly "discovered"
Metamorphic code – Type of code used by computer viruses
Möbius strip – Non-orientable surface with one edge
Münchhausen trilemma – A thought experiment used to demonstrate the impossibility of proving any truth
Ontological paradox – Sequence of events which cause each other
Optical feedback – Loop delay that occurs when a video camera is pointed at its own playback video monitor
Ouroboros – Symbolic serpent with its tail in its mouth
Penrose stairs – Impossible object
Perpetual motion – Work being continuously done without an external input of energy
Phoenix (mythology) – Immortal bird that is cyclically reborn
Pitch circularity – Fixed series of tones that appear to ascend or descend endlessly in pitch
Predestination paradox – Sequence of events which cause each other
Reflexivity (social theory) – Circular relationships between cause and effect
Rock paper scissors – Hand game for two players
Shepard tone – Auditory illusion
Three hares – Motif of three hares in threefold rotational symmetry
Tupper's self-referential formula – Formula that visually represents itself when graphed