We think of the world around us as "3 dimensional". This "dimensionality" is a construct (on an axis of "some degree of" utility) to assist thought, picturing, and/or communication about, our experience of our presumed existence - more accurately, about our experience of experience (we could say "experience of perception" but that posits perception). Back to engineering? Firstly some visual maths, since at heart we are all visual learners :D Mathematically, in our perception we are said to be engaged in a "reducing" or reduction of complexity problem, for which problem in our analog domain of existence, the human organism seems efficiently adapted. For the beginner, start with the problem of reducing a 2 dimesional image, a circle on a sheet of paper, to 1 dimension - i.e. points and segments on a line. (A circle reduces to point(s) whereas a disc reduces to a segment (finite or "short" line) as they "pass through" the "line of perception", respectively.) So imagine ("image within") a piece of paper with a long line on it, and a circle "falling through" that "line of perception" - that is, when any part of the circle is touching the line, it appears as a point when it first touches the line, or as two points as it crosses through the line. Adding the "dimension" of time, and a circle moving with "linear velocity" down our page, the points on the line expand apart, then come back together, finally disappearing as the circle passes completely through the line - those two points in this scenario move apart from one another (and vice versa) on our line of perception with a velocity which would appear as a "sine wave" if graphed. So in this first example we have "reduced 3D to 2D" in this "problem of perceiving a 2D circle, in 1 dimension" i.e. from the point of view of a single dimension (our line of perception). Analogously we can reduce a 3 dimensional object to 2 dimensions, and a canonical example, the sphere "moving through" a piece of paper or "plane of perception". This can of course be extended to a 3 dimensional "volume of perception" and the analogous "4D spheroid" as it moves through the volume of perception appearing as first a tiny but growing sphere, reaches it's "largest perceived" spherical size as observed from the volume of perception, and then similarly reducing and finally disappearing. So that's the geometric ("mathematical") visualization needed as our starting point. Now "engineering". We start with our eye. https://en.wikipedia.org/wiki/Eye The human eye has a planar (hemispherical or rather concave for practical purposes, but we may set this aside for our purpose of understanding) component called the retina. The retina contains special photosensitive cells which operate (biach i oper ate) as a real time camera ("photographic sensor") "taking pictures of" our 3 dimesional delusion thus down converting "reality" into a "two dimensional image" for easier processing by our brains. The concavity of the retina maximises field of view for a given pixel (photosensitive cell) density. We have 2 eyes, which is handy if we lose or damage one, and also allows the brain to construct a far more accurate "representation of reality" within our minds, since the light ("pixel" intensity, color and location) 'offsets' or deltas, provides the data necessary for depth calculations. Perception is a function of many things (not least e.g. inebriation) including bandwidth, frequency, sesitivity, interference, noise and more - all of which may be applied to the eye as much as to cameras. Next example is the ear - our ears pick up "sound" vibrations. Two ears collect sufficient data for the brain to process out ("reduce") to some degree, the 3 dimensionality of the sound (where it comes from, is it moving in space time?) and our environment (are there objects in my en#vironment reflecting the sound?). The ears are comprised of a spiral form - a sea-shell type cavity increasing the distance over which sound vibrations are sampled within the sound sampling cavity, and also filtering for frequency over that distance, maximising per-Hz sensitivity and spatial information (this description is a bit loose - feel free to try to describe this more accurately). The spiral provides a physical space condensing or reduction of space required for given operating characteristics, and increasing the bandwidth of (at least "possible") frequency sampling. Putting this together, a single iris is inherently planar, reducing a volumetric target of observation to a planar representation for processing and analysis, the ear is a spiral, providing a similar signal data reduction function, although seems to be more like a line than a plane, and when we have two such spatially separated data collection points, the signal processing unit (brain) can deduce 3 dimesionality from the two 2D data sampling/reduction units (or in the case of the ears, quite arguably 1D data sampling/reduction units!). That is we can say: - the down sampling ('reduction of dimensionality') makes the data analysis and signal transmission loads practical, and - the duplication of the (down) sampling unit, at sufficiently disparate locations, allows the data processing unit to reconstruct certain of the higher order (in this case 3) dimensionality So duplication of a 2 dimesional signal sampler, provides for reconstruction (in some form) of a 3 dimensional signal. And so we could argue that triplication (or more) of a 2 dimensional signal sampler could possibly provide for a 4 dimensional reconstruction of sorts. We can use signal analysis physics/ math to determine parameters of dimesionality which might be "in the haystack" of reduced or down-sampled data, and different frequency and energy limits etc ("that's like, vibrations, dood!"). Finally, and here's a kicker, insufficient signal sampling sensitivity may be overcome with sufficient sampling device replication (and also with increased device sensitivity): As the "2D retina photosensitive cells array" is to "3D space" … … so too the "3D helix gene bath of cells in our body" is to "4D supra dimesional space". You are an aerial complex - tune yourself, know thyself, go within.