Tuesday 28 May 2024

Stephen's Sausage Roll

Stephen's Sausage Roll is a puzzle videogame, created by Stephen Lavelle and first released on the 18th of April, 2016. I first played it two years later, on April 19, 2018. A few weeks after that I completed the game. Enthralled by what I experienced, I first attempted to find the words to clarify my experience in 2019, almost five years ago. Back then I was unable to express what makes Stephen's Sausage Roll so unique that its shadow looms over any other puzzle game I've played since. It nevertheless has been on my mind in all that time and I've replayed it in full somewhere in 2020-2021. Recently I've started playing it again, and this time I feel like I had some insight into what the game forces you to do that makes it such a radical experience.

The premise of Stephen's Sausage Roll is seemingly simple, even banal. It's a sokoban-style game, which means that the player controls a character and you have to push objects on a grid-based system to put them in specific positions. You play as an unnamed character, often called Stephen. You're holding a oddly-shaped fork and you roll sausages onto grills.
The game consists of an overworld of interconnected levels, each containing a single puzzle. Within a group of puzzles the player is free to choose in which order they want to solve the levels. To enter a level one simply aligns 'Stephen' with the Stephen-shaped translucent outline in the overworld. 

You then enter a level that contains the player's character, one or more grill tiles and one or more sausages.

The objective of each level is then to grill all sausages on both sides. You do this by pushing the sausages so they roll over.

When all sausages are grilled, you have to return to your starting position. This is non-trivial in some levels.

And that's it. That's the game's entire foundation. Grilling slightly more than 200 sausages is all you have to do. It's a simple premise, but it reaches a great depth through its pitch-perfect execution.

Reaching this depth is only possible because everything in Stephen's Sausage Roll has a function. Even if rolling sausages seems like a silly premise, the shape of the sausages determine their movement. Each sausage is two tiles long and one tile wide, but most importantly it is cylindrical, has a top and a bottom and therefore it can roll over. This in turn determines its movement, which can be distinguished between a roll and a slide. The comically oversized fork of Stephen makes it so your player character also takes up two tiles, but he instead has a front and a back and a centre of rotation that is clearly placed on only one of the tiles. In later levels it also becomes possible to separate the fork from the figure, which brings a whole new dimension into play.
The same exacting attention to detail is unmistakeably present in the level design. The world of Stephen's Sausage Roll is fully interconnected, the overworld is simply what happens when all the ground tiles from all the levels are present at the same time.

This is all the more impressive because in each of the levels, taken on their own, there are exactly enough elements present to solve, or sometimes create, the puzzle. There is not a single superfluous tile in the entire game. At times there are open 'fields', but their function is usually only to make the awkward movement of the character more tolerable to the player. 

Take The Great Tower, for example. This is commonly the level where the shock of possibilities really dawns on the player. Up until that point all sausage rolling has taken place in a two-dimensional plane and then this daunting behemoth shows up unannounced. Yet the level itself is quite generous. There is a large field where the player can mess about with the mechanics while dismantling the tower, so they can (sub)consciously teach themselves how the sausages (inter)act in a third dimensional plane.

And teaching yourself how Stephen Sausage Roll works is a vital part of the gameplay. The game is often described as 'difficult' and when this is seen as a negative aspect, one of the criticisms aimed at the game is that it doesn't do a good job at teaching its rules to players. I would very strongly disagree with this sentiment, however, because it simply isn't true. There aren't a lot of rules or mechanics present in Stephen's Sausage Roll. In fact, I already covered nearly all of them in this post so far. Thus knowing the rules to the puzzles in Stephen's Sausage Roll is almost trivial and anybody with the slightest knowledge of video game mechanics will instantly be familiar with them.
What's unique about the game is not the complexity of its rule set, but that it's only concerned with the ultimate logical consequences of that set of rules. From a few simple rules, Stephen's Sausage Roll extracts a great number of complex, and at times unintuitive, possibilities. What's more is that it expects of you to understand these right from start of the game.
The first levels in Stephen's Sausage Roll are likely the most difficult to the player, because they have to internalise the logical outcomes of a system they aren't yet familiar with. Most levels in Stephen's Sausage Roll demand that you reason backward from the unseen, but implied, end state of the puzzle. The player has to reverse engineer the puzzle-making process, so to speak.

As a player you have to understand the final position of all the sausages if you want to be able to solve the puzzles. This doesn't mean that if you know an end position you have also solved the puzzle, as is the case in many other games. No, in Stephen's Sausage Roll this is simply the beginning. Nowhere is this more clear than in an early puzzle titled the Clover.

At first glance the level appears relatively straightforward, as all sausages are located directly next to a four-tile grill. Yet when you proceed to grill the sausages in that way you ultimately end up in the following predicament when you attempt to return to your starting position:

This is an 'unexpected' outcome because as a player you're initially only thinking of the abstract goal of the puzzles: to grill some sausages. Yet returning to your starting position is a crucial aspect of the puzzles and thus it is not the grilling of the sausages that one needs to be concerned with, but grilling the sausages so that they end up in a particular position. In order to do this, you need to trace your steps backwards from the end goal and see what initial movements can lead to this outcome.

This backwards reasoning is somewhat common in puzzle games, but Stephen's Sausage Roll is the only game I can think of that absolutely requires this kind of understanding if you want to progress in the game at a reasonable pace. There is very little, if anything, in the game that entertains a player with an incomplete understanding of its mechanics. If you experience frustration in Stephen's Sausage Roll, and there will be plenty of moments where you do, it's only because of your own incomplete understanding. From the very beginning the game always provides you with all the knowledge you need, but not a single sliver more than that.
Even if I am now quite familiar with the possibilities of Stephen's Sausage Roll, in all my playthroughs I found that the game got easier, not harder, as I went on. Even as the complexities of the puzzles grows exponentially towards the end of the game, having much more experience with its rules means that it's far easier to see and understand the solutions to these more complex puzzles.
And at the point where you as a player have acquired this necessary insight into its mechanics, then the levels look less and less like puzzles, but more like an attempt to express a certain idea about the game and its possibility-space. In nearly all instances these are elegantly communicated through the minimal, yet absurdist design, and the game becomes a beautiful glimpse into the mind of Lavelle as a designer.

Although I've come much closer to expressing my feelings about Stephen's Sausage Roll with this text than I did on previous attempts, I still don't believe I've quite been able to articulate the exact nature of what makes Stephen's Sausage Roll so extraordinary. After six years this short text of adjectives is apparently the best I can do. Therefore I strongly suggest you play the game for yourself and experience first hand what I and many other commentators have difficulty finding the right words for.

Tuesday 7 May 2024

Please (don't) take a seat

 At the recent solo-exhibition of Sung Hwan Kim at the van Abbe Museum I encountered the following set up:

In case my low-quality phone photograph isn't clear enough, what we have here are two rectangular black objects made of wood. They are of near-identical height and placed on the floor about 1,5 meters in front of a screen that is showing a video.
What is strange about this is that one is marked 'Please take a seat', while on the other it's written to 'Please don't sit'. The first is meant as a bench to sit on and watch a video, the second is a box that houses a projector.
To include two almost identical objects with opposite functions is such an absurdly stupid decision that it could have easily been the premise for a Monthy Phython sketch.

Friday 26 April 2024

The Difficulty of Forgetting

A few months after my grandmother died, there were a few of her belongings left at my parents' house, including a simple painting of a farm. 'We tried to see if it was worth something', my dad said. 'And it was about sixty euro's', I immediately replied. 'Yeah! Yeah, it was!', he said, surprised, as if he had no idea how I spent my time in the preceding fifteen years. He naturally was also a little bit disappointed with the painting's value. It had hung so long in my grandmother's house that the whole family probably thought it was very valuable.
In either case, I don't know where that painting is currently. Perhaps in my parents'  attic, or at an uncle's house. I can't even rule out the possibility it was simply thrown away.

My point is that whenever I see the claim that an artist was 'rediscovered', they were never forgotten or unrecognised in the first place. It takes a substantial amount of attention, effort, space and other resources to preserve any kind of artwork for more than a few months, let alone decades or centuries. So whenever I see more than a single work turn up by a 'forgotten' artist, you just know that that's a false claim. Somebody somewhere cared very deeply about those works and went to great lengths to safeguard them.

Tuesday 23 April 2024


The chemical benzene is apparently an attractive proposition for a number of artists.
Benzene has a unique spatial structure that makes it stand out from other molecules. It has been known since the 1800's that benzene consists of six carbon atoms and six hydrogen atoms. It was also known that carbon-based molecules are generally spatially arranged in connecting tetrahedrons. As this is impossible to achieve with an equal number of carbon and hydrogen atoms, it has been a long standing mystery on how these atoms were arranged in the molecule.
The beginning of the solution was offered in 1865 by August Kekulé, who proposed a geometrically flat hexagonal 'ring' structure with alternating 'double bonds', which he visualised in the following manner:

This is the actual model Kekulé built to demonstrate the structure. It is now in the collection of the University Museum in Ghent, Belgium, where Kekulé was living at the time.
In this model the black balls represent carbon atoms, the white balls are hydrogen atoms and the connecting metal rods are single and double bonds. Such bonds are connections between atoms created through both atoms 'sharing' a pair of electrons. In a double bond two pairs of electrons are thus shared between two adjacent atoms.
After the 19th century, quantum mechanics and molecular orbital theory have further refined this view. Yet the general principle of benzene consisting of six carbon atoms in a planar hexagonal shape still stands, with the six hydrogen atoms arranged like 'antennas' at opposite ends of, and in the same plane as, the hexagon. As such, it is usually graphically depicted in one of the following ways:

It's obvious that artist Monira Al Qadiri had these (simplified) graphical structures in mind when she started on her work 'Benzene' in 2022. This work consists of a series of sculptures where, according to her, 'the scientific geometry of benzene's chemical compounds are rendered into glass sculptures, in order to highlight the grip that this perfumed molecule has on our lives.' While most of these structures are straightforward translations of the above shown schematics into three-dimensional glass shapes, one of them caught my attention:

To any chemist it's immediately obvious that this is completely impossible and has nothing to do with any kind of reality. Al Qadiri's claim to 'the scientific geometry' is thus hardly scientific.
To understand why this is so you need a bit of technical understanding about delocalized π-electrons in the structure of benzene and where possible lone pairs of electrons would go if their hydrogen atoms were displaced. Since providing such understanding isn't really attainable within the scope of this blogpost, let me just say that Al Qadiri's sculpture is a bit like stating that this is what a functional bicycle looks like:

Al Qadiri further places emphasis on the smell of benzene. She says that benzene is 'a colourless and highly flammable liquid with a sweet smell, it is partially responsible for the aroma around petrol stations, and is thus classified as an ‘aromatic hydrocarbon.’ ' It is in this manner that she makes the connection between benzene and the petrochemical industry. While benzene is (non-exclusively) extracted from crude oil, the connection she makes with petrol stations is partially a false one. Benzene is a minor part of gasoline, of only approximately 1% by volume. It thus doesn't contribute greatly to any particular core property of gasoline, least of all it's flammability. This flammability is much more influenced by short-chain alkanes like butane and hexane, which have far lower boiling points and oxidize much more rapidly. In fact, a mixture of benzene and benzene-like molecules called BTEX is sometimes added to gasoline to reduce its combustibility.
The second part of her statement, where she links the smell of benzene to its classification as an 'aromatic hydrocarbon' misunderstands cause and effect. It is true that in 1855 August Wilhelm Hoffman gave the classification of 'aromatic acids' to a number of compounds, even if not all them had  a distinctive smell. We now know the core component of those 'aromatic acids' was the presence of a benzene-like structure and the 'aromatic' moniker has thus stuck for those kind of molecules. Their properties and uses vary wildly, however. Besides benzene, photographic developer is also aromatic and so are the basic building blocks of DNA. Al Qadiri's observation is thus far removed from an explanation of any of benzene's properties or 'the grip it has on our lives'.

Less poetically interpretative, but equally misinformed, is a much earlier example by the hand of Bernar Venet. At the time known for his appropriated 'scientific' drawings, Venet made the following 'drawing' in 1966:

The text, in French, describes the 'importance of Kekulé's formula'. According to Venet this 'formula allowed us to interpret the hydrogenation of benzene to cyclohexane and the chlorination to benzene hexachloride.'
I'm not exactly sure what he's attempting to express here. Hydrogenation of alkenes to alkanes using platinum catalysts was first published in 1874, some ten years after Kekulé's discovery, and I'm not entirely sure this process would work on the more stable structure of benzene. How it helps us 'interpret' this process is thus unclear to me, as it implies that the discovery of the process came after the explanation that process.
Furthermore, the process of 'chlorination' generally refers to simple addition of chlorine to a molecule. In this case you would thus end up with hexachlorocylcohexane, not hexachlorobenzene as is claimed in Venet's text. But it is possible to make hexachlorobenzene from benzene with a substitution reaction, so lets just assume Venet meant this instead. In that case he describes the structural formula of 'hexachlorobenzene' as C6H12Cl6. This formula is simply impossible. A carbon atom can only be connected to four other atoms at the same time. In a ring structure, two of those possibilities are already taken up by the neighbouring carbon atoms, which leaves us with a total of 12 'free' spaces. As we have 6 chlorine atoms and 12 hydrogen atoms in Venet's proposed formula, we apparently need to fit 18 atoms into the 12 available possibilities. The correct formula would thus be C6H6Cl6 for hexachlorocyclohexane or C6Cl6 for hexachlorobenzene.
Furthermore, in order to show the formation of benzene, Venet uses the so-called trimerisation of alkyne as his example. This is an unusual choice from a chemical point of view. Firstly because this process was first described in 1866, one year after Kekulé published his formula. And secondly because t
rimerisation is a very difficult reaction to perform. It has a very high activation energy, thus requiring high temperatures of >800 ºC, and even then the end result isn't pure benzene but a mixture of different products. Therefore this reaction was far from efficient, or common, until a different process was developed in the late 1940's that involves the use of catalysts, which made alkyne trimerisation a viable reaction in routine synthesis work.
Thus while I generally enjoy the drawings of Venet for their stylized simplicity, it's best to not actually read the text that's contained in them.

Richard Venlet is a third artist I've encountered who has an interest in benzene and it's structure. He published a booklet with the title Kekulé in 2011. Its starting point was the anecdote of August Kekulé's first insight into the structure, which took place while he was living in Ghent, Belgium. 

Venlet presents no claims to scientific knowledge and his little booklet seems to be nothing more than a happenstance that reflects his interest in hexagonal shapes, like the ones he used for a series of floor panels created for Maniera two years prior:

As is clear to see, in the booklet Venlet presents a repeating pattern of hexagons, as he would show in his exhibitions. The reference to Kekule and his structure of benzene is thus a pure formal one. Nevertheless, it must be pointed out that the structure he presents is chemically impossible. The flat structure of such a system, like in the well-known graphene, is only possible through the 'double bonds' present in benzene, or rather its delocalized π-system. Such a system is usually represented by the addition of extra lines in certain places, which are missing in Venlet's drawing. Although seemingly a small difference, this has great consequences for the spatial arrangement of such a molecule, which would put an impossibly large strain on the system that Venlet represents. The following illustration hopefully gives a sense of the factual differences that are left out of such simplified illustrations:

It should be easy to see that a so-called saturated system that Venlet has drawn is far more crowded and therefore possesses very little room to move and wiggle, something all atoms want to do. While it might be possible on a smaller scale like the above illustration, a large field like the one presented in Venlet's booklet will in reality simply fall apart and find a different conformation.

In conclusion I should once again state that although I have never expected otherwise and can occasionally enjoy the fantasy-rich interpretations of artists, it's nevertheless a good idea to presume that an artist's factual understanding of the natural sciences is negligible. When I asked as a chemist I know why he enjoyed working with artists, he simply said 'it's so nice to see people who are unburdened by knowledge'.

Monday 22 January 2024

Testing, Testing.

Recently I wrote about some watercolours I've made. Since then I've found some scientific literature on the subject, after discovering that the 'coffee ring effect' is the scientific name of a ring shaped deposit found after a drop of liquid has dried. It's a relatively new field of study, with major research only being done since the late 1990's. This literature does confirm my basic assumption of the movement of the paint particles, which is explained by capillary flow. The literature also shows that there are many competing phenomena and variables at play, which are difficult to measure and analyse. Many of the papers I found focus on variables like temperature, relative humidity and electromagnetic influences, most of which effect the rate of evaporation.

I've done some experiments to test the influence of some of these parameters on the appearance of my own drops of watercolour, with some notable results.

First I tried to measure the influence of temperature. The results of this were mostly inconclusive. To test the influence of temperature, I uniformly applied the droplets at three different temperatures, to see if their appearance would differ after drying. The expected result from some of the literature would be that a higher temperature creates a more even distribution throughout the drying droplet. Various mechanisms have been suggested on how this works, including a greater evaporation at the contact surface with the air, which causes greater flow inside the droplet, as well as a 'surface capture' effect of particles at the contact surface.
In the rudimentary testing I have done I however didn't notice any significant effects of temperature on how uniformly the paint spread through the drying droplet:

Three drops dried at different temperatures

In this image there are three droplets of about 2 mm in diameter, made with Winsor and Newton's Payne's grey watercolour paint. The first was made on a substrate that's cooled below 0ºC, the middle was made at room temperature and the last one was heated after application in an oven to about 70ºC. It's clear that there is little significant variation between these three droplets, thereby giving indication that temperature, at least on this scale and with these materials, is not a significant contributing factor for the distribution of the pigments in the drying droplet.
However, the influence of temperature might be dependent on the exact chemical composition of the pigments, in combination with corresponding changes in the binders used. The following image consists of the results of the same experiment, showing Daniel Smith's Hematite Genuine watercolour paint, in duplicate, at <0ºC, room temperature and ~70ºC, respectively.

Two sets of three drops dried at different temperatures

What one can observe here is greater ring formation with a cooled substrate and more concentration at the center at elevated temperatures. So much so that the ring where the pigment is deposited is not even found at the outer edge of the droplet, which is something I have not observed in other situations. This behaviour is also the exact opposite of what the literature would have us expect.

When examining the literature, it must also be noted that most of the literature on the coffee ring effect seeks to eliminate it, because in an analytical or manufacturing context its existence is commonly detrimental to achieving uniform depositions or measurements. Relatively little literature thus exists on controlling the formation of the ring itself, and as far as I can tell, all research is done on colloids that are mixed prior to droplet formation. Little to no research has been done on the effects of introducing a colloid to an existing droplet. Yet I've found indications that for our purposes this provides a lot of control on the exact formation of the coffee ring, as can be seen in the following image:

Four different ways of introducing the paint

From left to right, this is a simple droplet of a diluted suspension of Winsor and Newton Payne's grey watercolour, a water droplet to which a diluted suspension was added at the centre point of the droplet after droplet formation, a water droplet to which a diluted suspension was added at the right edge of the droplet after droplet formation and a water droplet to which a near-saturated suspension was added at the right edge of the droplet after droplet formation.
As you can see, the two leftmost droplets dried nearly identical, even if their method of application was very different. For the third droplet from the left, paint was added later at an angle on the right edge with the paper, and this saw most of the pigment end up around the full perimeter of the droplet. This process was repeated with a higher concentration of pigment in the last droplet and while this contained far more pigment than the other three droplets, still most of it stayed at the perimeter of the droplet, with even more seemingly remaining at the initial point of introduction.

My explanation for this is that a similar outward pushing effect is at work here, inhibiting the possibility for pigments to enter the centre of the droplet through gravity or other forces.
It must however be also noted that in some degree this is dependent on the exact shape of the droplet and again the composition of the paint.

Three different ways of introducing the paint

In this image we have a droplet with a homogenous solution of Daniel Smith's Venetian Red water colour paint, followed by a saturated solution of the same paint added at the right edge of a droplet of water and ultimately a heavily diluted solution added at the right edge of a droplet of water. They each have their distinctive appearances, which differ subtly from the previous experiment with Payne's grey, most notably with the later introduction of a saturated solution. This produced a light centre with a thick edge in the previous experiment, while it created a mostly even spread with a thin edge in the latter example.

Even though it's difficult to observe this behaviour in real time and at actual scale, I believe the observations from the previous two figures is related to the behaviour of the pigment at the droplet's contact surface with air. I did a test where I placed a small saturated spot of Payne's grey watercolour on a piece of paper, let it dry, and then added a water droplet, without physically disturbing the spot of paint. What I found after this droplet had dried is that the paint had spread uniformly throughout the droplet, with a clear coffee ring effect present. There thus is a tendency for the paint to be distributed inside the droplet if it gets far enough inside. 

Adding water to a dried spot of paint

Generally speaking, predicting the exact behaviour of the interaction of a fluid and a colloid is complex and very difficult, as can be seen in the following example:

Introducing two paints into a single droplet

In this image two different watercolour paints are added to a single droplet. The droplet at the top was a diluted solution of Daniel Smith's Quinacridone Gold water colour paint, to which a saturated solution of Daniel Smith's Quinacridone Red was added on the right side at an angle. The droplet at the bottom was pure water, to which Quinacridone Gold was first added at the top and then Quinacridone Red was added on the right side at an angle. As is clearly visible, the latter process resulted in a nearly homogenous mixture, while the first gave a degree of separation between in the colours in the dried droplet.
However, I then repeated this experiment using Daniel Smith's Quinacridone Gold and Winsor & Newton's Payne's grey.

Introducing two paints into a single droplet

Here the same procedure was followed, with the Payne's Gray being added first, followed by Quincridone Gold on the right side at an angle. The way the paints mixed was the opposite of what I observed in the previous experiment. On this occasion the Quinacridone Gold mixed better with the droplet of diluted water colour, while the two paints stayed separated when added in sequence to a droplet of pure water. At the present time I have no simple explanation for this seeming contradiction in behaviour.

Lastly I want to note another characteristic I hadn't considered up until this point, which is the influence of magnetic effects on the droplets. Naturally electromagnetic effects are strong if there are ferromagnetic pigments present in the paint. Especially in the case of paints that contain a mixture of magnetic and non-magnetic pigments, introducing a magnetic field during the drying process produces interesting effects that can be easily controlled with the presence of any magnetic field. 

In conclusion, about a month has past since the previous post and I have still made some new observations about the behaviour of the watercolour paint inside a droplet. Some of these observations seemingly contradict the explanations found in current scientific literature, while others provide a possibility for new methods that are hitherto unexplored.