Recursion

Recursion is a visual distortion in which the external environment or sections of it appear to repeat and nest within themselves in a self-similar, fractal-like fashion. The visual field seems to fold inward upon itself, with a portion of what one sees being duplicated at a smaller scale within itself, and that duplicate containing yet another smaller copy, and so on — creating an impression of infinite depth or infinite regression, much like the visual effect of standing between two parallel mirrors.

This effect typically manifests as specific sections of the visual field detaching and reproducing themselves in progressively smaller or larger iterations. A doorway might appear to contain a smaller doorway within it, which contains an even smaller one, spiraling infinitely inward. Alternatively, the entire visual panorama may seem to zoom into itself, creating a tunnel-like sensation of falling into recursive layers of the same scene. The recursion can follow geometric patterns — spiraling, tiling, or branching — and often incorporates the fractal-like geometry that characterizes many psychedelic visual effects.

Recursion is most commonly induced under the influence of moderate to heavy dosages of psychedelic compounds such as LSD, psilocybin, mescaline, and DMT. It can also occur under the influence of dissociatives such as ketamine and DXM, though it tends to manifest somewhat differently with these substances, often appearing more blocky or angular rather than smoothly flowing. The effect tends to appear during peak intensity and is more likely to emerge when focusing on textured surfaces, repeating patterns, or detailed visual scenes.

The experience typically occurs spontaneously and rarely sustains itself for more than several seconds before dissolving back into normal vision, only to re-emerge moments later. However, at higher doses, recursion can become more persistent and elaborate, with the self-similar loops becoming increasingly complex and encompassing larger portions of the visual field. Some users report that closing their eyes during recursion reveals even more elaborate versions of the effect in their closed-eye visuals.

Subjective reports frequently describe recursion as one of the more awe-inspiring and intellectually stimulating visual effects, as it creates an unmistakable impression of mathematical infinity made visible. Users often compare the experience to the visual representation of fractals such as the Mandelbrot set or Sierpinski triangle, noting that the effect seems to reveal an inherent recursive structure underlying visual perception itself. The experience can produce feelings of wonder, vertigo, or slight disorientation depending on its intensity and the viewer's state of mind.

Recursion is closely related to other visual distortions that alter the spatial structure of the visual field, including symmetrical texture repetition, environmental patterning, and visual drifting. When these effects co-occur, they can create extraordinarily complex visual scenes in which the environment seems to transform into an endlessly self-referencing geometric tapestry.