Geometry is the experience of a person's field of vision becoming partially or completely encompassed by ever-shifting, colourful, and complex geometric patterns, form constants, phosphenes, shapes, fractals, and colours.     
Geometry is rarely motionless and is generally both fast-moving and constantly self-changing in its shape and style. During this process, the geometry naturally drifts across the visual field while fluidly transitioning through many distinct states and forms.
At greater levels of intensity, these geometric forms can often become structured and organized in a manner that presents genuine information to the person experiencing them, far beyond the perception of meaningless (though complex) shapes and colours. These geometric representations often feel as though they depict extraordinarily detailed and innately understandable information about specific concepts and neurological processes that occur within the brain. This particular aspect of geometry can lead into incredibly complex and nuanced experiences such as visual exposure to inner mechanics of consciousness, and visual exposure to semantic concept network.
Geometry is often accompanied by other coinciding effects such as internal hallucinations, environmental patterning, and drifting. It is most commonly induced under the influence of moderate dosages of psychedelic compounds such as LSD, psilocybin, and mescaline. However, it can also occur to a lesser extent under the influence of cannabis, MDMA, and dissociatives. This effect is capable of manifesting itself across seven different levels of intensity. These tend to depend on the dosage, but can fluctuate wildly in their intensity due to external triggers such as a person's set and setting. The individual levels are defined below:
Motion and Colour
Partially Defined Geometry
Fully Defined Geometry
Partially overriding visual perception
Depending on the person and the specific substance consumed, hallucinogenic geometry can manifest in an incredibly wide variety of aesthetic styles that are often subjectively interpreted quite differently between people. However, there are certain themes and descriptive terms that people commonly use to describe them. For example, many people will claim that LSD geometry looks synthetic and digital in style; however, in comparison, psilocybin geometry looks organic. Outside of this, other commonly used descriptive terms include but are not limited to: natural, synthetic, digital, organic, mystical, cartoony, realistic, tribal, ancient, eldritch, sacred, hyperspatial, mechanical, cosmic, and alien.
In terms of geometry's less subjective potential stylistic differences, these can be broken down into the following variations:
Intricate vs Simple
Geometry can either present itself as incomprehensibly intricate and complex in its appearance or simplistic, basic and comprehensible even at higher doses. For example, the geometry associated with dissociatives tends to be consistently overly simplistic in form while most psychedelics produce significantly more intricate geometry.
Algorithmic vs Abstract
Algorithmic geometry can appear to follow mathematical rules and logically consistent forms in its design. This often results in high amounts of fractals and semi-predictable shapes. In contrast, geometry can also be completely abstract or random in its appearance in a way that contains an infinite amount of completely unpredictable variety.
Unstructured vs Structured
Geometry can either present itself as completely disorganized and unstructured across a 2-dimensional plane, or it can form and condense across the surfaces of a variety of 3-dimensional mechanical and ever-shifting structures.
Dimly lit vs Brightly lit
Geometry can either present itself as extremely dark and hard to make out from its background or, in contrast, can be brightly lit and extremely easy to distinguish from its background. For example, the geometry associated with dissociatives tends to be consistently darker in appearance while most psychedelic geometry is significantly brighter.
Multicoloured vs Monotone
The colour scheme of geometry can be extremely varied and multicoloured, or it can have little to no colour variety in a manner that is usually comprised of grays, purples and blacks.
Flat shading vs Glossy shading
The shading of geometry can either be flat, bright and simplistic, or it can be glossy with depth, gradients, highlights, and shading.
Sharp edges vs Soft edges
Geometry can have sharp edges which are extremely well-defined around the perimeter, sometimes with thick black outlines around their edges. In contrast, they can also be soft and blurred around the edges, merging seamlessly into each other in a manner which does not affect its intricacy.
Large vs Small
The size of geometry can either be extremely large and zoomed in, or it can be fine and zoomed out in a manner that does not affect its overall level of intricacy.
Fast vs Slow
In terms of its speed, geometry can shift and morph so fast into itself that the amount of information presented to the tripper in extremely short periods of time becomes very difficult to process. In contrast, geometry can move slowly and comprehensibly, gradually swirling and shifting into themselves to present forms that can be observed at a much higher level of detail.
Smooth vs Jittery
In terms of its motion, geometry can either move smoothly with a seemingly high frame rate, or it can be jittery in its motion with lag and a lower frame rate.
Round corners vs Angular corners
Geometry can either have mostly rounded and circular corners or mostly sharp corners with pointed and angular geometry.
Non-immersive vs Immersive
Non-immersive geometry can be manifested in front of one’s face in a manner that feels as if it was being presented on a screen without a distinct sense of size or distance attributed to it. In contrast, immersive geometry can feel as if one is completely immersed in and surrounded by it with a distinct sense of attributed size and distance.
Consistent vs Progressive
Geometry can be consistent and steady in its intensity, complexity and visibility regardless of disturbances within the external environment. In contrast, progressive geometry can manifest in such a way that disturbances and sensory input such as bright lights, loud noises and distractions within the external environment will reset the intensity, complexity and visibility to a baseline level. Undisturbed darkness can aid in progressive geometry steadily rising in complexity.
Visual geometry was the aspect of the psychedelic experience that most quickly convinced me that these substances are incredibly profound and essential tools for humanity. Almost a decade ago as a young 17-year-old undergoing my first couple of hallucinogenic experiences, I found myself immediately fascinated by the sheer incomprehensibility of the beautiful patterns which my mind was producing. Not only were these geometric patterns complex beyond anything I had ever seen, but they were so impossibly complex in their forms that I perhaps naively believed if even a short recording of high-level geometry could be somehow brought back to the real world, it would change the face of society forever.
Based on my personal experiences, I firmly believe that geometry is not simply another form of hallucination, but instead a result of neurological signals and processes from various regions of the brain bleeding into the visual cortex and being reinterpreted as complex geometric forms in a manner which is comparable to that of synaesthesia. This would explain multiple aspects of the effects behaviour, such as the way in which geometry commonly feels as if it is an innately understandable visual representation of one's emotional state, sensory input, and even complex concepts or thoughts. If this is true, it implies that psychedelic geometry is the profound experience of being able to indirectly see the hidden architecture and complex programming of human consciousness.
Another aspect of geometry that myself and others have found very intriguing is that psychedelic geometry often follows the aesthetic themes of various artwork and writing styles from historical societies, such as Aztecs, Mayans, Egyptians, Tibetans, etc.
Based purely upon my own potentially flawed speculation, there are a couple of relatively plausible explanations behind this. Perhaps our culture simply associates psychedelia with mysticism and ancient societies in a manner which results in these themes displaying themselves within our collective experience of psychedelic geometry. Perhaps these societies experienced the very same imagery under the influence of psychedelic plants and took inspiration from this within their artwork, architecture, and alphabets. Maybe psychedelic geometry manifests itself in a manner which is, on some level, a visual representation of the same neurological processes that allowed ancient humans to create language and artwork in the first place, thus generating a variety of somewhat consistent aesthetic themes throughout the humans that experience them, regardless of their cultural or historical context.
Nevertheless, none of these speculative ideas feel particularly satisfactory to me, but I do still hope that this particular aspect of psychedelic geometry is more closely examined and understood on a a scientific level within my lifetime.
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