Choosing low-tech visual styles for games

A month ago, I participated in Ludum Dare, a 48-hour game development contest. This was the first time I finished a game-like project since about 2005.

The theme of the contest was "connected worlds". I made a game called Quantum Dash that experiments with parallel universes as a central game mechanic. The player operates in three universes at the same time, and when connecting "interdimensional cords", the differences between these universes explosively cancel each other. The "Dash" part in the name refers to the Boulder Dash style grid physics I used. I found the creation process very refreshing, I am quite happy with the result considering the circumstances, and I will very likely continue making games (or at least rapid prototypes thereof).

My relationship with computer games became somewhat dissonant during the nineties. At that time, the commercial industry became radically more centralized and profit-oriented. Eccentric European coder-auteur-heroes disappeared from computer magazines, giving way to American industry giants and their campaigns. There was also the rise of the "gamer" subculture that I considered rather repulsive from early on due to its glorification of hardware upgrades and disinterest towards real computer skills.

Profit maximization in the so-called serious game industry is largely driven by a specific, Hollywood-style "bigger is better" approach to audiovisual esthetics. That is, a strive for photorealism. This approach is, of course, very appealing to shareholders: It is easy to imagine the grail -- everyone knows what the real world looks like -- but no one will ever reach it despite getting closer all the time. Increases in processing power and development budgets quite predictably map to increases in photorealism. There is also inherent obsolescence: yesterday's near-photorealism looks bad compared to today's near-photorealism, so it is easy to make consumers desire revamped versions of earlier titles instead of anything new.

In the early noughties, the cult of photorealism was still so dominant that even non-commercial and small-scale game productions followed it. Thus, independent games often looked like inadequate, "poor man's" versions of AAA games. But the cult was starting to lose its grip: independent games were already looking for new paths. In his spring 2014 paper, game researcher Jesper Juul gives 2005 as an important year in this respect: since 2005, the Grand Prize winners of the Independent Games Festival have invariably followed styles that diverge from the industrial mainstream.

Juul defines "Independent Style" as follows: "Independent Style is a representation of a representation. It uses contemporary technology to emulate low-tech and usually “cheap” graphical materials and visual styles, signaling that a game with this style is more immediate, authentic and honest than are big-budget titles with high-end 3-dimensional graphics."

The most prominent genre within I.S. is what Juul calls "pixel style", reminiscent of older video game technology and also overlapping with the concept of "Computationally Minimal Art" I formulated a few years ago. My game, Quantum Dash, also fits in this substyle. I found the stylistic approach appealing because it is quick and easy to implement from scratch in a limited time. Part of this easiness stems from the fact that CMA is native to the basic fabric of digital electronic computers. Another attracting aspect is the long tradition of low-tech video games which makes it easy to reflect prior work and use the established esthetic language.

Another widely used approach simulates art made with physical materials such as cut-out paper (And Yet It Moves) or wax pastels on paper (Crayon Physics). Both this approach and the aforementioned pixel style apparently refer to older technologies, which makes it tempting to generalize the idea of past references to other genres of I.S. as well. However, I think Juul somewhat stumbles with this attempt with styles that don't have a real historical predecessor: "The pixel style 3d games Minecraft and Fez also cannot refer to an earlier time when 3d games were commonly made out of large volumetric pixels (voxels), so like Crayon Physics Deluxe, the historical reference is somewhat counterfactual, but still suggests a simpler, if nonexistent, earlier technology."

I think it would be more fruitful to concentrate on complexity than history when analyzing Independent Style. The esthetic possibility space of modern computing is mind-bogglingly large. It is easy to get lost in all the available potential complexity. However, by introducing constraints and stylistic choices that dramatically reduce the complexity, it is easier even for a solo artist to explore and grasp the space. The contraints and choices don't need to refer to any kind of history -- real or counterfactual -- to be effective.

The voxel style in Minecraft can still be considered somewhat historical -- a 3D expansion of grid-based 2D games such as Boulder Dash. However, I suspect that the esthetic experimentation in independent games will eventually lead to a much wider variety of styles and constraints -- including a bunch that cannot be explained with historical references.

The demoscene has been experimenting with different visual styles for a long time. Even at times when technical innovation was the primary concern, the goal was to find new things that just look good -- and realism was just one possible way of looking good. In 1996, when realtime raytracing was a hot new photorealistic thing among democoders, there was a production called Paper by Psychic Link that dropped jaws with its paper-inspired visuals -- a decade before paper simulation became trendy in the independent games scene. Now that the new PC hardware no longer challenges the demo artist the way it used to, there is much more emphasis on stylistic experimentation in non-constrained PC demos.

Because of this longer history of active experimentation, I think it would be useful for many more independent game developers to look for stylistic inspiration in demoscene works. Of course, not all the tricks and effects adapt well to games, but the technological and social conditions in their production are quite similar to those in low-budget games. After all, demos are real-time-rendering computer programs produced by small groups without budgets, usually over relatively short time periods, so there's very little room for "big-budget practices" there.

Here's a short list of demos with unique esthetic elements that might be able to inspire game esthetics as well. Two of them are for 8-bit computers and the rest for (semi-)modern PCs.

• Metamorphosis by ASD
• IX by Moppi Productions
• Your Song is Quiet part 2 by Inward and TPOLM
• Royal Temple Ball by Synesthetics
• Antifact by Limp Ninja
• Weed by Triebkraft and 4th Dimension
• hwr2 by Kosmoplovci

I'm expanding into game design and development primarily because I want to experiment with the power of interactivity, especially in relation to some of my greater-than-life goals. So, audiovisuals will be a secondary concern.

Still, due to my background, I want to take effort in choosing a set of simple and lightweight esthetic approaches to be used. They will definitely be computationally minimal, but I want to choose some fresh techniques in order to contrast favorably against the square-pixel style that is already quite mainstream in independent games. But that'll be a topic for another post.

The relationship between "New Aesthetic" and Computationally Minimal Art

A couple of weeks ago, something called "New Aesthetic" was brought to my attention. It is difficult to find any sort of coherent definition for the idea, but it seems like an umbrella label for a wide variety of visual things that somehow look computational, often in not-so-computational contexts. The main spreader of the meme is apparently a Tumblr blog that collects pictures of things such as pixellated glitches in textiles, real-life voxel sculptures, mugs decorated with website graphics, digitally glitched photographs, satellite images as well as all kinds of other things that evocate suitably futuristic associations.



Despite the profound vagueness of the umbrella term, it is not difficult to notice the general trend it refers to. Just a decade ago, a computationally inspired real-life object would have been a unique novelty item, but nowadays there are such things all around us. I mentioned an aspect of this trend back in 2010 in my article on Computationally Minimal Art, where I noticed that "retrocomputing esthetics" is not just thriving in its respective subcultures (such as demoscene or chip music scene) but popping up every now and then in mainstream contexts as well -- often completely without the historical or nostalgic vibe usually associated with retrocomputing.

As the concept of "New Aesthetic" overlaps a lot of my ponderings, I now feel like building some semantics in order to relate the ideas to one another:

"New Aesthetics", as I see it, is a rather vague umbrella term that contains a wide variety of things but has a major subset that could be called "Computationally Inspired".

"Computationally Inspired" is anything that brings the concepts and building blocks of the "digital world" into non-native contexts. T-shirts, mugs and other real-life objects decorated with big-pixel art or website imagery are obvious examples. In a wide sense, even anything that makes the basic digital building blocks more visible within a digital context might be "Computationally Inspired" as well: big-pixel low-fi computer graphics on a new high-end computer, for example.

"Computationally Minimal" is anything that uses a very low amount of computational resources, often making the digital building blocks such as pixels very discernible. Two years ago, I defined "Computationally Minimal Art" as follows: "[A] form of discrete art governed by a low computational complexity in the domains of time, description length and temporary storage. The most essential features of Computationally Minimal Art are those that persist the longest when the various levels of complexity approach zero."

We can see that Computationally Inspired and Computationally Minimal have a lot of overlap but neither is a subset of another. Cross-stitch patterns are CM almost by definition as they have a limited number of discrete "pixels" with a limited number of different colors, but they are not CI unless they depict something that comes from the "computer world", such as video game characters. On the other hand, a sculpture based on a large amount of digitally corrupted data is definitely CI but falls out of the definition of CM due to the size of the source data.

What CM and CI and especially their intersection have in common, however, is the tendency of showing off discrete digital data and/or computational processes, which gives them a lot of esthetic similarity. In CI, this is usually a goal in itself, while in CM, it is most often a side-effect of the related goal of low computational complexity. In either case, however, the visual result often looks like big-pixel graphics. This has caused confusion among many New Aesthetic bloggers who use adjectives such as "retro", "8-bit" or "nostalgic" when referring to this phenomenon, when what they are witnessing is just a way how the essence of digital technology tends to manifest visually.

There has been a lot of on-line discussion revolving New Aesthetic during the past month, and a lot of it seems like pseudo-intellectual, reality-detached mumbo-jumbo to me. In order to gain some insight and substance, I would like to recommend all the bloggers to take serious a look into the demoscene and other established forms of computer-centric expression. You may also find out that a lot of this stuff is actually not that new to begin with, it has just been gaining a lot of new momentum recently.

Ancient binary symbolism and why it is relevant today

It is a well-known fact the human use of binary strings (or even binary numbers, see Pingala) predates electronics and automatic calculators by thousands of years.

Divination was probably the earliest human application for binary arrays. There are several systems in Eurasia and Africa that assign fixed semantics to bitstrings of various lengths. The Chinese I Ching gives meanings to the 3- and 6-bit arrays, while the systems used in the Middle East, Europe and Africa tend to prefer groups of 4 and 8 bits.

These systems of binary mysticism have been haunting me for quite many years already. As someone who has been playing around with bits since childhood, I have found the idea of ancient archetypal meanings for binary numbers very attractive. However, when studying the actual systems in order to find out the archetypes, I have always encountered a lot of noise that has blocked my progress. It has been a little bit frustrating: behind the noise, there are clear hints of an underlying logic and an original protosemantics, but whenever I have tried to filter out the noise, the solution has escaped my grasp.

Recently, however, I finally came up with a solution that satisfies my sense of esthetics. I even pixelled a set of "binary tarot cards" for showing off the discovery:


For a more complete summary, you may want to check out this table that contains a more elaborate set of meanings for each array and also includes all the traditional semantics I have based them on.

Of course, I'm not claiming that this is some kind of a "proto-language" from which all the different forms of binary mysticism supposedly developed. It is just an attempt to find an internally consistent set of meanings that match the various traditional semantics as closely as possible.

Explanation

In my analysis, I have translated the traditional binary patterns into modern Leibnizian binary numbers using the following scheme:

This is the scheme that works best for I Ching analysis. The bits on the bottom are considered heavier and more significant, and they change less frequently, so the normal big-endian reading starts from the bottom. The "yang" line, consisting of a single element, maps quite naturally to the binary "1", especially given that both "yang" and "1" are commonly associated with activity.

I have drawn each "card picture" based on the African shape of the binary array (represented as rows of one or two stones). I have left the individual "stones" clearly visible so that the bitstrings can be read out from the pictures alone. Some of the visual associations are my own, but I have also tried to use traditional associations (such as 1111=road/path, 0110=crossroads, 1001=enclosure) as often as they feel relevant and universal enough.

In addition to visual associations, the traditional systems have also formed semantics by opposition: if the array 1111 means "journey", "change" and "death", its inversion 0000 may obtain the opposite meanings: "staying at home", "stability" and "life". The visual associations of 0000 itself no longer matter as much.

The two operations used for creating symmetry groups are inversion and mirroring. These can be found in all families of binary divination: symmetric arrays are always paired with their inversions (e.g. 0000 with 1111), and asymmetric arrays with their reversions (e.g. 0111 with 1110).

Because of the profound role of symmetry groups, I haven't represented the arrays in a numerical order but in a 4x4 arrangement that emphasizes the mutual relationships via inversion and mirroring. Each of the rows in the "binary tarot" picture represents a group with similar properties:

• The top row contains the four symmetrical arrays (which remain the same when mirrored).
• The second row contains the arrays for which mirroring and inversion are equivalent.
• The two bottom rows represent the two groups whose members can be derived from each other solely by mirroring and inversion.
  

The semantics within each group are interrelated. For example, the third row ("up", "in", "out", "down") can be labelled "the directions". In order to emphasize this, I have chosen a pair of dichotomies for each row. For example, the row of the directions uses the dichotomies "far-near" and "horizontal-vertical", and the array called "up" combines the poles "far"+"vertical". All the dichotomies can be found in my summary table.

The arrays in the top two groups have an even parity while those on the bottom two groups have an odd parity. This difference is important at least in Al-Raml and related systems, where the array getting the role of a "judge" in a divination table must have an even parity; otherwise there is an error in the calculation.

The members of each row can be derived from one another by eXclusive-ORing them with a symmetrical array (0000, 1111, 0110 or 1001). For this reason, I have also organized the arrangement as a XOR table.

The color schemes used in the card pictures are based on the colors in various 16-color computer palettes and don't carry further symbolism (even though 0010 happens to have the meaning of "red" in Al-Raml and Geomancy as well). Other than that, I have abstained from any modern technological connections.

But why?

Our subjective worlds are full of symbolism that brings various mental categories together. We associate numbers, letters, colors and even playing cards to various real-world things. We may have superstitions about them or give them unique personalities. Synesthetics even do this involuntarily, so I guess it is quite a basic trait for the human mind.

Binary numbers, however, have remained quite dry in this area. We don't really associate them with anything else, so they remain alien to us. Even experts who are constantly dealing with binary technology prefer to hide them or abstract them away. This alienation combined to the increasing role of digitality in our lives is the reason why I think there should be more exposure for the various branches of binary symbolism.

In many cultures, binary symbolism has attained a role so central that people base their conceptions of the world on it. A lot of traditional Chinese cosmology is basically commentary of I Ching. The Yoruba of West Africa use the eight-bit arrays of the Ifa system as "hash codes" to index their whole oral tradition. Some other West African peoples -- the Fon and the Ewe -- extend this principle far enough to give every person an eight-bit "kpoli" or "life sign" at their birth.

I guess the best way to bring some binary symbolism to our modern technological culture might be using it in art. Especially the kind of art such as pixel art, chip music and demoscene productions that embrace the bits, bringing them forward instead of hiding them. This is still just a meta-level idea, however, and I can't yet tell how to implement in it practice. But once I've progressed with it, I'll let you know for sure!

What should big pixels look like?

There has been some fuss recently about a new algorithm that vectorizes pixel art. And yes, judging from the example pictures, this algorithm by Johannes Kopf and Dani Lischinski indeed seems to produce results superior to the likes of hq*x and scale*x or mainstream vectorization algorithms. Let me duplicate the titular example for reference:
Impressive, yes, but as in case with all such algorithms, the first question that came to my mind was: "But does it manage dithering and antialiasing?". The paper explicitly answers this question: no.

All the depixelization algorithms so far have been succesful only with a specific type of pixel art. Pixel art of a cartoonish style that has clear lines and not too many details. This kind of pixel art may have been mainstream in Japan, but in the Western sphere, especially in Europe, there has been a strong tradition of optimalism: the tendency of maximizing the amount of detail and shading within the limited grid of pixels. An average pixel artwork on the Commodore 64 or the ZX Spectrum has an extensive amount of careful manual dithering. If we wish to find a decent general-purpose pixel art depixelization algorithm, it would definitely need to take care of that.

I once experimented by writing an undithering filter that attempts to smooth out dithering while keeping non-dithering-related pixels intact. The filter works as follows:

• Flag a pixel as a dithering candidate if it differs enough from its cardinal neighborhood (no more than one of the four neighbors are more similar to the reference pixel than the neighbor average).

• Extend the area of dither candidates: flag a pixel if at least five of its eight neighbors are flagged. Repeat until no new pixels are flagged.

• For each flagged pixel, replace its color with the weighed average of all the flagged pixels within the surrounding 3x3 rectangle.

Would it be possible to improve the performance of a depixelization algorithm by first piping the picture thru my undithering filter? Let's try out. Here is an example of how the filter manages with a fullscreen C-64 multicolor-mode artwork (from the demoscene artist Frost of Panda Design) and how the results are scaled by the hq4x algorithm:

The undithering works well enough within the smooth areas, and hq4x is even able to recognize the undithered areas as gradients and smooth them a little bit further. However, when looking at the border between the nose and the background, we'll notice careful manual antialiasing that even adds some lonely dithering pixels to smooth out the staircasing. My algorithm doesn't recognize these lonely pixels as dithering, and neither does it recognize the loneliest pixels in the outskirts of dithered gradients as dithering. It is a difficult task to algorithmically detect whether a pixel is intended to be a dithering pixel or a contour/detail pixel. Detecting antialiasing would be a totally different task, requiring a totally new set of processing stages.

There seems to be still a lot of work to do. But suppose that, some day, we will discover the ultimate depixelization algorithm. An image recognition and rerendering pipeline that succesfully recognizes and interprets contours, gradients, dithering, antialiasing and everything else in all conceivable cases, and rerenders it in a high resolution and color without any distracting artifacts. Would that be the holy grail? I wouldn't say so.

The case is that we already have the ultimate depixelization algorithm -- the one running in the visual subsystem of the human brain. It is able to fill in amazing amounts of detail when coping with low amounts of reliable data. It handles noisiness and blurriness better than any digital system. It can extrapolate very well from low-complexity shapes such as silhouette drawings or groups of blurry dots on a CRT screen.

A fundamental problem with the "unlimited resolution" approach of pixel art upscaling is that it attempts to fill in details that aren't there -- a task in which the human brain is vastly superior. Replacing blurry patterns with crisp ones can even effectively turn off the viewer's visual imagination: a grid of blurry dots in the horizon can be just about anything, but if they get algorithmically substituted by some sort of crisp blobs, the illusion disappears. I think it is outright stupid to waste computing resources and watts for something that kills the imagination.

The reason why pixel art upscaling algorithms exist in the first place is that sharp rectangular pixels (the result of nearest-neighbor upscaling) look bad. And I have to agree with this. Too easily recognizable pixel boundaries distract the viewer from the art. The scaling algorithms designed for video scaling partially solve this problem with their interpolation, but the results are still quite bad for the opposite reason -- because there is no respect for the nature of the individual pixel.

When designing a general-purpose pixel art upscaling algorithm, I think the best route would go somewhere between the "unlimited resolution" approach and the "blurry interpolation" approach. Probably something like CRT emulation with some tasteful improvements. Something that keeps the pixels blurry enough for the visual imagination to work while still keeping them recognizable and crisp enough so that the beauty of the patterns can be appreciated.

Nevertheless, I was very fascinated by the Kopf-Lischinski algorithm, but not because of how it would improve existing art, but for its potential of providing nice, organic and blobby pixels to paint new art with. A super-low-res pixel art painting program that implements this kind of algorithm would make a wonderful toy and perhaps even vitalize the pixel art scene in a new and refreshing way. Such a vitalization would also be a triumph for the idea of Computationally Minimal Art which I have been advocating.

Defining Computationally Minimal Art (or, taking the "8" out of "8-bit")

Introduction

"Low-tech" and "8-bit" are everywhere nowadays. Not only are the related underground subcultures thriving, but "retrocomputing esthetics" seems to pop up every now and then in mainstream contexts as well: obvious chip sounds can be heard in many pop music songs, and there are many examples of "old video game style" in TV commercials and music videos. And there are even "pixel-styled" physical products, such as the pictured watch sold by the Japanese company "&design". I'm not a grand follower of popular culture, but it seems to me that the trend is increasing.

The most popular and widely accepted explanation for this phenomenon is the "nostalgia theory", i.e. "People of the age group X are collectively rediscovering artifacts from the era Y". But I'm convinced that there's more to it -- something more profound that is gradually integrating "low-tech" or "8-bit" into our mainstream cultural imagery.

Many people have became involved with low-tech esthetics via nostalgia, but I think it is only the first phase. Many don't experience this phase at all and jump directly to the "second phase", where pixellated graphics or chip sounds are simply enjoyed the way they are, totally ignoring the
historical baggage. There is even an apparent freshness or novelty value for some people. This happens with audiences that are "too young" (like the users of Habbo Hotel) or otherwise more or less unaffected by the "oldskool electronic culture" (like many listeners of pop music).

Since the role of specific historical eras and computer/gaming artifacts is diminishing, I think it is important to provide a neutral conceptual basis for "low-tech esthetics"; an independent and universal definition that does not refer to the historical timeline or some specific cultural technology. My primary goal in this article is to provide this definition
and label it as "Computationally Minimal Art". We will also be looking for support for the universality of Computationally Minimal Art and finding ur-examples that are even older than electricity.

A definition: Computationally Minimal Art

Once we strip "low-tech esthetics" from its historical and cultural connections, we will be left with "pixellated shapes and bleepy sounds" that share an essential defining element. This element stems from what is common to the old computing/gaming hardware in general, and it is perfectly possible to describe it in generic terms, without mentioning specific platforms or historical eras.

The defining element is LOW COMPUTATIONAL COMPLEXITY, as expressed in all aspects of the audiovisual system: the complexity of the platform (i.e. the number of transistors or logic gates in the hardware), the complexity of the software (i.e. the length in bits of the program code and static data), as well as the time complexity (i.e. how many state changes the computational
tasks require). A more theoretical approach would eliminate the differentiation of software and hardware and talk about description/program length, memory complexity and time complexity.

There's little more that needs to be defined; all the important visible and audible features of "low-tech" emerge from the various kinds of low complexity. Let me elaborate with a couple of examples:

• A low computing speed leads to a low number of processed and output bits per time frame. In video output, this means low resolutions and limited color schemes. In audio output, this means simple waveforms on a low number of discrete channels.


• A short program+data length, combined with a low processing speed, makes it preferrable to have a small set of small predefined patterns (characters, tiles, sprites) that are extensively reused.


• A limited amount of temporary storage (emerging from the low hardware complexity) also supports the former two examples via the small amount of available video memory.


• In general, the various types of low complexity make it possible for a human being (with some expertise) to "see the individual bits with a naked eye and even count them".

In order to complete the definition, we will still have to know what "low" means. It may not be wise to go for an arbitrary threshold here ("less than X transistors in logic, less than Y bits of storage and less than Z cycles per second"), so I would like to define it as "the lower the better". Of course, this does not mean that a piece of low-tech artwork would ideally
constitute of one flashing pixel and static square-wave noise, but that the most essential elements of this artistic branch are those that persist the longest when the complexity of the system approaches zero.

Let me therefore dub the idealized definition of "low-tech art" as Computationally Minimal Art (CMA).

To summarize: "Computationally Minimal Art is a form of discrete art governed by a low computational complexity in the domains of time, description length and temporary storage. The most essential features of Computationally Minimal Art are those that persist the longest when the
various levels of complexity approach zero."

How to deal with the low complexity?

Traditionally, of course, low complexity was the only way to go. The technological and economical conditions of the 1970s and 1980s made the microelectronic artist bump into certain "strict boundaries" very soon, so the art needed to be built around these boundaries regardless of the artist's actual esthetic ideals. Today, on the other hand, immense and virtually non-limiting amounts of computing capacity are available for practically everyone who desires it, so computational minimalism is nearly always a conscious choice. There are, therefore, clear differences in how the low complexity has been dealt with in different eras and
disciplines.

I'm now going to define two opposite approaches to low complexity in computational art: optimalism (or "oldschool" attitude), which aims at pushing the boundaries in order to fit in "as much beauty as possible", and reductivism (or "newschool" attitude), which idealizes the low complexity itself as a source of beauty.

Disclaimer: All the exaggeration and generalization is intentional! I'm intending to point out differences between various extremities, not to portray any existing "philosophies" accurately.

Optimalism

Optimalism is a battle of maximal goals against a minimal environment. There are absolute predefined boundaries that provide hard upper limits for the computational complexity, and these boundaries are then pushed by fitting as much expressive power as possible between them. This approach is the one traditionally applied to mature and static hardware platforms by the
video game industry and the demoscene, and it is characterized by the appreciation of optimization in order to reach a high content density regardless of the limitations.

A piece of traditional European-style pixel graphics ("Frog, Landscape and a lot of Clouds" by oys) exemplifies many aspects of optimalism. The resolution and color constraints of a video mode (in this case, non-tweaked C-64
multicolor) provide the hard limits, and it is the responsibility of the artist to fill up the space as wisely and densely as possible. Large single-colored areas would look "unfinished", so they are avoided, and if it is possible to fit in more detail or dithering somewhere, it should be done. It is also avoidable to leave an available color unused -- an idea which leads to the infamous "Dutch color scheme" when applied to high/truecolor video modes.

When applied to chip music, the optimalist dogma tells, among all, to fill in all the silent parts and avoid "simple beeps". Altering the values of as many sound chip registers per frame as possible is thought to be efficient use of the chip. This adds to the richness of the sound, which is though to correlate with the quality of the music.

On platforms such as the Commodore 64, the demoscene and video game industry seem to have been having relatively similar ideals. Once an increased computing capacity becomes available, however, an important difference between these cultures is revealed. Whenever the video game
industry gets more disk space or other computational resources, it will try to use it up as aggressively as possible, without starting any optimization efforts until the new boundaries have been reached. The demoscene, on the other hand, values optimality and content density so much that it often prefers to stick to old hardware or artificial boundaries in order to keep the "art of optimality" alive. The screenshot is from the 4K demo "Artefacts" by Plush (C-64).

Despite the cultural differences, however, the core esthetic ideal of optimalism is always "bigger is better"; that an increased perceived content complexity is a requirement for increased beauty. Depending on the circumstances, more or less pushing of boundaries is required.

Reductivism

Reductivism is the diagonal opposite of optimalism. It is the appreciation of minimalism within a maximal set of possibilities, embracing the low complexity itself as an esthetic goal. The approach can be equated with the artistic discipline of minimal art, but it should be remembered that the idea is much older than that. Pythagoras, who lived around 2500 years ago, already appreciated the role of low complexity -- in the form of mathematical beauty such as simple numerical ratios -- in music and art.

The reductivist approach does not lead to a similar pushing of boundaries as optimalism, and in many cases, strict boundaries aren't even introduced. Regardless, a kind of pushing is possible -- by exploring ever simpler structures and their expressive power -- but most reductivists don't seem to be interested in this aspect. It is usually enough that the output comes out as "minimal enough" instead of being "as minimal as possible".

The visuals of the recent acclaimed Flash-based platformer game, VVVVVV, are a good example of computational minimalism with a reductivist approach. The author, Terry Cavanagh, has not only chosen a set of voluntary "restrictions" (reminiscent of mature computer platforms) to guide the
visual style, but keeps to a reductivist attitude in many other aspects as well. Just look at the "head-over-heels"-type main sprite -- it is something that a child would be able to draw in a minute, and yet it is perfect in the same iconic way as the Pac-Man character is. The style totally serves its purpose: while it is charming in its simplicity and downright naivism, it
shouts out loud at the same time: "Stop looking at the graphics, have fun with the actual game instead!"

Although reductivism may be regarded as a "newschool" approach, it is possible to find some slightly earlier examples of it as well. The graphics of the 1986 computer game Thrust, for example, has been drawn with simple geometrical lines and arcs. The style is reminiscent of older vector-based arcade games such as Asteroids and Gravitar, and it definitely serves a technical purpose on such hardware. But on home computers with bitmapped screens and sprites, the approach can only be an esthetical one.

Optimalism versus Reductivism

Optimalism and reductivism sometimes clash, and an example of this can be found in the chip music community. After a long tradition of optimalism thru the efforts of the video game industry and the demoscene, a new kind of cultural branch was born. This branch, sometimes mockingly called
"cheaptoon", seems to get most of its kicks from the unrefined roughness of the pure squarewave rather than the pushing of technological and musical boundaries that has been characteristic of the "oldschool way". To an optimalist, a reductivist work may feel lazy or unskilled, while an
optimalist work may feel like "too full" or "too refined" to a reductivist mindset.

Still, when working within constraints, there is room for both approaches. Quite often, an idea is good for both sides; a simple and short algorithm, for example, may be appreciated by an optimalist because the saved bytes leave room for something more,, while a reductivist may regard
the technical concept as beautiful on its own right.

Comparison to Low-Complexity Art

Now I would like to compare my definition of Computationally Minimal Art to another concept with a somewhat similar basis: Jürgen Schmidhuber's Low-Complexity Art.

While CMA is an attempt to formalize "low-tech computer art", Schmidhuber's LCA comes from another direction, being connected to an ages-old tradition that attempts to define beauty by mathematical simplicity. The specific mathematical basis used in Schmidhuber's theory is Kolmogorov complexity, which defines the complexity of a given string of information (such as a picture) as the length of the shortest computer program that outputs it. Kolmogorov's theory works on a high level of generalization, so the choice of language does not matter as long as you
stick to it.

Schmidhuber sees, in "down-to-earth coder terms", that the human mind contains a built-in "compressor" that attempts to represent sensory input in a form as compact as possible. Whenever this compression process succeeds well, the input is perceived as esthetically pleasing. It is a well-studied fact that people generally perceive symmetry and regularity as more beautiful than unsymmetry and irregularity, so this hypothesis of a "mental compressor" cannot be dismissed as just an arbitrary crazy idea.

Low-Complexity Art tests this hypothesis by deliberately producing graphical images that are as compressible as possible. One of the rules of LCA is that an "informed viewer" should be able to perceive the algorithmic simplicity quite easily (which also effectively limits the time complexity of the algorithm, I suppose). Schmidhuber himself has devised a system based
on indexed circle segments for his pictures.

The above picture is from "Superego", a tiny pc demo I made in 1998. The picture takes some tens of bytes and the renderer takes less than 100 bytes of x86 code. Unfortunately, there is only one such picture in the demo, although the 4K space could have easily contained tens of pictures. This is because the picture design process was so tedious and counter-intuitive --
something that Schmidhuber has encountered with his own system as well. Anyway, when I encountered Schmidhuber's LCA a couple of years after this experiment, I immediately realized its relevance to size-restricted demoscene productions -- even though LCA is clearly a reductivist approach as opposed to the optimalism of the mainstream demoscene.

What Low-Complexity Art has in common with Computationally Minimal Art is the concern about program+data length; a minimalized Kolmogorov complexity has its place in both concepts. The relationship with other types of complexity is different, however. While CMA is concerned about all the types of complexity of the audiovisual system, LCA leaves time and memory complexity out of the rigid mathematical theory and into the domain of a "black box" that processes sensory input in the human brain. This makes LCA much more theoretical and psychological than CMA, which is mostly concerned about "how the actual bits move". In other words, LCA makes you look at
visualizations of mathematical beauty and ignore the visualization process, while CMA assigns an utmost importance to the visualizer component as well.

Psychological considerations

Now, an important question: why would anyone want to create Computationally Minimal Art for purely esthetical reasons -- novelty and counter-esthetic values aside? After all, those "very artificial bleeping sounds and flashing pixels" are quite alien to an untrained human mind, aren't they? And even many fans admit that a prolonged exposure to those may cause headache.

It is quite healthy-minded to assume that the perception mechanisms of the human species, evolved during hundreds of millions of years, are "optimized" for perceiving the natural world, a highly complex three-dimensional environment with all kinds of complex lighting and shading conditions. The extremely brief technological period has not yet managed to alter the "built-in defaults" of the human mind anyhow. Studies show, for example, that people all over the world prefer to be surrounded by wide-open landscapes with some water and trees here and there -- a preference that was fixed to our minds during our millions of years on the African savannah.

So, the untrained mind prefers a photorealistic, high-fidelity sensory input, and that's it? No, it isn't that simple, as the natural surroundings haven't evolved independently from the sensory mechanisms of their inhabitants. Fruits and flowers prefer to be symmetric and vivid-colored because animals prefer them that way, and animals prefer them that way because it is beneficial for their survival to like those features, and so on. The natural world is full of signalling which is a result of millions of years of coevolutionary feedback loops, and this is also an important source for our own sense of esthetics. (The fish in the picture, by the way, is a Synchiropus splendidus, photographed by Luc
Viatour.)

I'm personally convinced that natural signalling has a profound preference for low complexity. Symmetries, regularities and strong contrasts are important because they are easy and effortless to detect, and the implementation requires a relatively low amount of genetic coding on both
the "transmitter" and "receiver" sides. These are completely analogous to the various types of computational complexity.

So, why does enjoying Computationally Minimal Art require "mental training" in the first place? I think it is not because of the minimality itself but because of certain pecularities that arise from the higher complexity of the natural world. We can't see individual atoms or even cells, so we haven't evolved a built-in sense for pixel patterns. Also, the sound generation
mechanisms in nature are mostly optimized to the constraints of pneumatics rather than electricity, so we don't really hear squarewave arpeggios in the woods (although some birds may come quite close).

But even though CMA requires some special adjustment from the human mind, it is definitely not alone in this area. Our cultural surroundings are full of completely unnatural signals that need similar adjustments. Our music uses instruments that sound totally different from any animal, and
practically all musical genres (apart from the simplest lullabies, I think) require an adjustment period. So, I don't think there's nothing particularly "alien" in electronic CMA apart from the fact that it still hasn't yet integrated in our mainstream culture.

CMA unplugged

The final topic we cover here is the extent where Computationally Minimal Art, using our strict definition, can be found. As the definition is independent from technology, it is possible to find ur-examples that predate computers or even electricity.

In our search, we are ignoring the patterns found in the natural world because none of them seem to be discrete enough -- that is, they fail to have "human-countable bits". So, we'll limit ourselves to the artifacts found in human culture.

Embroidery is a very old area of human culture that has its own tradition of pixel patterns. I guess everyone familiar with electronic pixel art has seen cross-stitch works that immediately bring pixel graphics in mind. The similarities have been widely noted, and there have been href="http://www.spritestitch.com/">quite many craft projects inspired by old video games. But is this just a superficial resemblance or can we count it as Computationally Minimal Art?

Cross-stitch patterns are discrete, as they use a limited set of colors and a rigid grid form which dictates the positions of each of the X-shaped, single-colored stitches. "Individual bits are perceivable" because each pixel is easily visible and the colors of the "palette" are usually easy to tell apart. The low number of pixels limits the maximum description length, and one doesn't need to keep many different things in mind while working either. Thus, cross-stitch qualifies all the parts of the definition of Computationally Minimal Art.

What about the minimization of complexity? Yes, it is also there! Many traditional patterns in textiles are actually algorithmic or at least highly repetitive rather than "fully hand-pixelled". This is somewhat natural, as the old patterns have traditionally been memorized, and the memorization is much easier if mnemonic rules can be applied.

There are also some surprising similarities with electronic CMA. Many techniques (like knitting and weaving) proceed one complete row of "pixels" at a time (analogous to the raster scan of TV-like displays), and often, the set of colors is changed between rows, which is corresponds very well to the use of raster synchronization in oldschool computer graphics. There are even peculiar technique-specific constraints in color usage, just like there are similar constraints in many old video chips.

The picture above (source) depicts a pillow knitted with the traditional Fair Isle technique. It is apparent that there are two colors per "scanline", and these colors are changed between specific lines (compare to rasterbars). The patterns are based on sequential repetition, with the sequence changing on a per-scanline basis.

Perhaps the most interesting embroidery patterns from the CMA point of view are the oldest ones that remain popular. During centuries, the traditional patterns of various cultures have reached a kind of multi-variable optimality, minimizing the algorithmical and technical complexity while maximizing the eye-pleasingness of the result. These patterns may very well
be worth studying by electronic CMA artists as well. Things like this are also an object of study for the field of ethnomathematics, so that's another word you may want to look up if you're interested.

What about the music department, then? Even though human beings have written music down in discrete notation formats for a couple of millennia already, the notes alone are not enough for us. CMA emphasizes the role of the rendering, and the performance therefore needs to be discrete as well. As it seems that every live performance has at least some non-discrete variables, we will need to limit ourselves to automatic systems.

The earliest automatic music was mechanical, and arguably the simplest conceivable automatic music system is the musical box. Although the musical box isn't exactly discrete, as the barrel rotates continuously rather than stepwise, I'm sure that the pins have been positioned in an engineer's accuracy as guided by written music notation. So, it should be discrete enough to satisfy our demands, and we may very well declare the musical box as being the mechanical counterpart of chip music.

Conclusion

I hope these ideas can provide food for thought for people interested in the various forms of "low-tech" electronic art as well as computational art or "discrete art" in general. I particularly want people to realize the universality of Computationally Minimal Art and how it works very well outside of the rigid "historical" contexts it is often confined into.

I consciously skipped all the cultural commentary in the main text on my quest for proving the universality of my idea, so perhaps it's time for that part now.

In this world of endless growth and accumulation, I see Computationally Minimal Art as standing for something more sustainable, tangible and crafty than what the growth-oriented "mainstream cultural industry" provides. CMA represents the kind of simplicity and timelessness that is totally immune to the industrial trends of fidelity maximization and planned obsolescence. It is something that can be brought to a perfection by an individual artist,
without hiring a thousand-headed army of specialists.

As we are in the middle of a growth phase, we can only guess what kind of forms Computationally Minimal Art will get in the future, and what kind of position it will eventually acquire in our cultural framework. We are living interesting times indeed.