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I write, therefore I am

With this variation on a famous statement by the philosopher Descartes, I would like to express that the act of writing about what happens in my life is important to me.

Sunday, April 12, 2026

Links

Tuesday, April 8, 2026

Exhibitions

This afternoon, I visited the exhibition Over Water with photographs by Joop Overkleeft. It has a series about soldiers placing a Bailey bridge and some from his digital graphics.

Next, I went to Concordia and watched the Idem et Idem exhibition again. One of the artists was present and I talked a little about her project. I also saw the video with the work of Kore Danaë Plunkett that that I cannot remember seeing the last time (probably because it was not projected). It was kind of a recording of a performance by her. The translation of the description of her work is: "My life is defined by duality and contradictions, as a result of my limitations. Chain armor and two-dimensional work are the spaces in which I explore these characteristic aspects of my identity."

In the evening, I went to the exhibition RE:-)CONNECT at B93 with works by second and third year students of the AKI. There were individual works by the following students on display:

They also had some collective works in coorporation with Tessa de Roo. There were two screen print collective works and two collages of works on the wall. I found those quite interesting. I talked with one of the students about this because you do not often see that artists worked together on an art work. I understood that it had come quite natural when they started working with screen printing.

Link

Tuesday, April 7, 2026

All flowers open

It looks like all flowers on our magnolia have opened. The first flowers opened on March 18. The leaves of most of those first flowers turned brown due to frost and have partly fell down already. The latest of the flowers that opened are on the side of the house, which receive far less sunshine than the side where the first flowers opened. We did get flowers for quite a long period this year. The flowers spread a lovely fragrance.

Link

Monday, April 6, 2026

Unexpected error messages

Since I finished replacing stage0 of live-bootstrap for x86 (32 bits) two months ago, I have been working on the x86 64 bits version. I heve now come as far as being able to compile the Tiny C Compiler sources, but the resulting compiler when compiling some sources gives some unexpected error messages, which seem to be correct (see commit 96ad3732). This will require some clever debugging. Maybe, should first test this compiler on some other sources.

Friday, April 3, 2026

Links

Thursday, April 2, 2026

Infinite mazes

I have been thinking about the construction of infinite mazes. When I say maze, I mean a maze on a infinite square grid (in all directions) where there is some way to calculate if there is a wall on each line segement of the grid and that the mazes is 'prefect' in the sense that the mazes has no cycles and that each square can be traveled to from every other square. The page Maze Classification give some algorithms for creating finite mazes on a rectangle (or square) of a square grid. There are only two algoritms: Wilson's algorithm and Aldous-Broder algorithm. For animations of these algorithms see the page Maze Algorithms. There is a simple method for generating infinite mazes from finite mazes of some fixed size n. The idea is to place grids of size n side to side on the grid. Asuming that the walls on the outside are all closed, it does not meet the requirement of a perfect maze. The idea is to create a maze of size n×n with 'rooms' of size n and have the openings determine where to add an opening between the mazes of size n. This should be repeated for every power of n. Asuming that the generation starts at the origin, one only has to generate this for a limited number of powers, depending on how far one moves from the origin. This technique is also explained on the page Making an Infinite Maze. This method does not really result in random mazes, because these kind of mazes will contain very long walls that are getting longer and longer the further one gets from the origin, which is rather rare in truely random mazes. How can be improve on this assuming that we start generating the maze from the center and do want to store as less as possible information, potentially being able to regenerate parts of the maze on demand? In some game, for example, the user would only see a limited part of the maze from above, or till a wall (or a certain distance) when from the inside. One idea is to generate the maze in chunks of n by n squares. In such a chunk it should not always be the case that there should be a path between all the squares. The idea is to start with an infinite grid that has no walls and start randomly adding walls inside a certain chunk as long as each sqaure still has a path to the 'outside'. If an additional chunk needs to be added, it will also be allowed to put walls on the 'sides' where the chunks touches chunks that already have been filled. Although this seems a good approach, it seems that it will reduce a different maze depending on the order in which the chunks are added. Even if everytime the same random sequence is used for each chunk, there is still a problem for the walls that needed to be placed on where the chunks meet. A solution could be to always generate the chunks in a 'fixed' order. If the order is truely fixed, for example in s spiral order around the center, one would have to generate more and more chunks if one is moving away from the center. A solution to this to introduce a dependend relation to the grid of chunks, were a chunk can only be generated when all the chunks it depended on are already generated. Maybe there is a way to define the dependend relation (with all other than the origin chunk depending on the origin chunk directly or indirectly) such that only a limited number of chunks need to be generated, possibly linear to the 'distance' to the origin.

Wednesday, April 1, 2026

Lone signpost in Mongolia

In episode 128 of season 8 of Itchy Boots titled 'Loneliness hits different in Mongolia 🇲🇳', Noraly Schoenmaker comes along a signpost in the middle of nowhere as can be seen starting at 13:53. This is along the grevel road A1701, which at many place is not a single road, but many parallel roads often spread out quite widely. So, it is rather interesting that there is a sign somewhere in the middle when most local just take one of the many tracks. I found a photo on Alamy.com that was taken by Daan Kloeg on Augustus 7, 2019. I contacted him and he promptly gave the location from which the photo was taken, allowing me to find the signpost on Google Earth. According to the satelite image on Google Earth the location of the signpost is 48°55'59.88"N 92° 2'19.38"E, a little west of the road on google maps and open street map, which might explain why I had not yet found it when I followed the road. (I am not sure whether I followed the complete road from the start to the end.) A little bit further (at 48°57'44.50"N 92° 2'34.98"E), she comes along another 'sign' with the words (if I have transcribed them correctly): 'өлгий' 'тавтай морил', and 'сум', which I understand means 'Welcome to Ölgii district. A little further she travels through a village called Ölgii.

Tuesday, March 31, 2026

Link

Sunday, March 29, 2026

Rotterdam Art Week (Day 4)

I traveled to Rotterdam to visited some locations of the Rotterdam Art Week. Below the works and/or artists I found noteworthy at the various locations. At Brutus Art Space, I saw the exhibition Autonomous curated by Ine Gevers. I found the following works noteworthy: I also saw the Sanitas Futurum exhibition by Atelier Van Lieshout.

At the Kunst & Complex building, I visited the studios of the artist. I found the following noteworthy:

At the Katoenhuis, I saw the exhibition Observatory: Cosmic Cabinet. I found the following works noteworthy:

At the exhibition Haute Photographie, I liked the following photographs:

At the Keilewerf, there were many people outside sitting and eating. I looked around inside and spend some time at Studio i Focus of Iris Veentjer and watch the machine to spinning machine for long fibers for the RietGoed project. Quite interesting.

At TEMT, I liked:

At the Museumplein, I saw the exhibition Learn to Love the Bomb organized by TECART. I found the followings works noteworthy:

At Kunsthal, I first saw the exhibition What the Hell Was I Thinking by David Shrigley. I found the following noteworthy:

I walked quickly through the exhibition Flowers Forever (because I was becoming a bit saturated with impressions) and only stopped looking at: I walked through the exhibition Mr. Goodman: The Kiteman. From the exhibition They have always been here by Kudzanai-Violet Hwami (Instagram), I liked:

At the S/ASH GALLERY, I saw the exhibition Interface. I found the following installation noteworthy:

Saturday, March 28, 2026

Link

Friday, March 27, 2026

Rotterdam Art Week (Day 2)

There was a broken layer of snow on the ground. At 9:15, I left by train to Rotterdam to visit a number of locations that take part of Rotterdam Art Week. Below the works and or artist that I found noteworthy at the various locations or exhibitions.

Prospects

Xaver Könneker. Samboleap Tol with Starlight. Pippilotta Yerna with Please, piece your bones into mine. Sophie Schreurs. Alice West. Marina Sulima with Of Climbing Vines and Copper Crystals. Natalia Jordanova with Latency Treshold, Latency Echo, Latency Transmission, Latency Amplification, and Latency Resonance. Suzanne Plomp with Framed in Veins (Substanctia), 2026. Isamo Thissen with De Melkfabriek,2025 and De Jacht, 2026. Obbe van der Weide with OS, Enforming, I, II, and III. Sander Coers with Intensive Care (Pietā), 2026. Clémence Lollia Hilaire with CRAA. Maja Simišić with a poster. Luca Tichelman with All the Wonders and the Ahhhh. Yara Veloso. Lea Novi with The Golden Garden. Ceola Tunstall-Behrens. Yara Jimmink. Aaryan Sinha. Christy Groen with Polyshift Horizon, Polyshift Full Frame, and Polyshift Portrait. Nelly Dansen with Project XXX. Steffi Reimers. mo Futures with Bizarre Beauty. Jonathan Tang. Aion Arribas with Dear Rubsters and Scisoring, Rubbing, Dildoing. Juni Mun. Saja Amro with Firearms Prohibited. Bonnie Ogilvie with Pin Me Down, Madeleine Elisabeth Peccoux with Moonbump, 2022-now. Sophie Allerding. Doris Kolpa. Marlot Meyer with Pneuma, 2025-2026. Jonathan Hielkema. Jildau Nijboer with Undercurrent I, 2026. Maaike Meindertsma with Shortcut. Ben Yau. Anto López Espinosa. Geo Barcan. Gus Drake with Landscapes in Motion. Jamal Ageli with Call Her the Morning Star, 2026. Ariane Toussaint with A Textile Room. Radvlad with Reduced Artifacts 4×. Pelle Schilling with a melting metal wire. Lena Longefay with La Chanson à Boire de la Douleur de la Terre. Loran van de Wier with Veganistische kaas sculpturen in vitrine. Katayoon Valamanesh with I Am Not The Girl, I am the Horse, 2025. Sixin Zeng with The 2.5D Nomad. Joppe Venema. Sarjon Azouz. Frances Rompas with The Exotic Fruit Section.

Art Rotterdam

Cordico

Rotterdam Photo

The New Current

The Usual

Kunstinstituut Melly

Garage Rotterdam

From the exhibition At the End(s) of the World: The Ground Is Shifting.

Thursday, March 26, 2026

Hail and wet snow

Just before noon, the sky turned dark after the sun was shinning, and shortly after, hail fell from the sky some of which stayed on the ground. Then the hail slowly changed into snow with at end even some real flakes. Soon after a blue sky appeared. Around this time the temperature at Twente Airport dropped about 5° Celsius.Around two, there was another similar, but not so strong, hailstorm, which was not followed by snow. At the end of the afternoon, there was again some wet snow during another shower. We are a bit worried about the flowers on our magnolia turning brown, also because the temperature the night is going to drop below zero.

Planning for Rotterdam Art Week

In the past days, I have been doing some planning for visitings Rotterdam Art Week. I am planning to go there tomorrow and Sunday. I have bought a pass-partout ticket allowing to visit me all locations that are require admission. My plan for tomorrow is to visit the following locations:

My plan for Sunday sofar is:

Sunday, March 22, 2026

Idem et Idem

In the afternoon, I saw the exhibition Idem et Idem (Latin for 'same and same') at Concordia with works by five AKI students. Works by the following students were on display.

Half of the flower

This afternoon, about half of the flowers on our magnolia opened as can be seen in the picture below:

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Link

Thursday, March 19, 2026

Counting ballots

Yesterday, the 2026 Dutch municipal elections were held and I helped with counting the ballots again. We only had 740 ballots at the polling station where I helped. We finished counting around 11 in the evening. I stayed together with the chair until the ballots and the official report were collected by separate people. We only made one small mistake during the counting of the ballots, which was corrected by a recount. This afternoon, I went to the central location where the official reports are checked and decided if a recount of the ballots is required. Up to now, I had always thought that everything was recounted. That would indeed require a lot of people. Shortly after we arrived, we were told to have some patience. Some group of people started to do some recounts. After about an hour waiting, the project leader came over and told that there was less recount work than they had counted for and that we were send home. I felt a bit dissapointed because I came to help with the recounting, but I did understand that it would be a bit useless if half of the people had come were waiting for a new recount while the others were busy. We did collect the chairs and fold the tables before we left. I decided to go into the city and I saw the exhibition AI Eyes for a third time. Then I saw the exhibition Pantaleon Hajenius & Haveman-Betman at Beeld & Aambeeld. Pantaleon Hajenius is making art works with objects that he find outside.

Wednesday, March 18, 2026

Some flowers opened

Yesterday at the end of the afternoon, I saw that some flowers on our magnolia had opened. Below a picture, I took of one of the flowers.

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I also checked the seeds we harvested last September. One of the two growing boxes had some white mold, probably saprophytic fungi, which are considered harmless. I did not see any evelopment, but I assume that it still too early. I will keep an eye on them and add water if needed.

Spiritual Enlightenment - The Damnedest Thing

I finished reading the book Spiritual Enlightenment - The Damnedest Thing by Jed McKenna, which I started reading four days ago. Jed Mckenna is a pseudonym of an unknown author. This is the first of nine books he wrote in total, but I get the impression that the following eight books do not add much to what he wants to tell. This book seems to describe a period of at most two weeks where he writes about the conversations he has with various people in around the house he is staying. It would not surprise me if it totally fictional but might still be based on actual conversations. He claims to be enlightened and that he became enlightened through a process that he calls Spiritual Autolysis, which comes down to evaluation everything you consider to be true. A long time ago, I already wrote something about what I think is true and also about being a sceptic, but the book did made me think about those things again. Although the author goes to great length to explain that many traditional sources are not the leading to enlightment, but to mystism at most, he still primarily quotes from those sources. He does not mention any recent scientific source about research into the brain and consciousness. Enjoyable read.

Tuesday, March 17, 2026

Dune: Part Three | Official Teaser Trailer

I watched the Official Teaser Trailer for Dune: Part Three, which is going to be released in nine months and one day. Although I did not like Dune: Part Two, I think I am still going to watch Part Three. This visuals, as expected, look good. Maybe know that Denis Villeneuve does not have the pressure anymore to deliver a block-buster, like I felt he had for Part Two, that it is going to be less of an action movie, although I understand that it will still have a lot of action. In teaser trailer has Paul asking advice with respect to the wars he is fighting, where Jessica answers: 'Your father did not start a war,' suggesting that Paul started the Jihad. That is indeed how it is brought in Part Two, but slightly more different from how it is written in Dune. Paul was not the active source of the Jihad, he was merely the fuse that caused it. The Fremen were oppressed for centuries and had become, also under the influence of the Missionaria Protectivia, religious fanatics where the sharing of the transformed Water of Life in the Sietch or Spice orgy awakening a very strong tribal consciousness. Chani explains: "When the tribe shares the Water we're together - all os us." (I fear that the Bene Gesserit where not aware of the explosive situation they had created with their interference.) Once a messiah appeared to save them, the transition from oppressed to oppressors was to be expected as we also have seen in our own world history up to today. Paul tried to avoid the Jihad to happen. It was in the tent with his mother that he first sensed it as something that could not be avoided. Yet, he made the decision to revenge the death of this father. In the first chapter of the second book of Dune, he wishpers "Now Harkonnen shall kill Harkonnen." He let all opportunities to avoid the Jihad pass. The last, I think, was when the visited the water basin where the water from Jamis was left. Paul is aware of the coming Jihad, but does nothing. When the leave the case he feels that "a vital moment had passed him." He thought he could take revenge and avoid the Jihad, but in the end he could not and after being unable to avoid it, embraced it. This often how things happen in life when people are overcome by evil. Instead of chosing to show the danger of messianic faiths, Villeneuve chose to make Paul the villian causing the Jihad.

Link

Monday, March 16, 2026

Steam

This morning, when I was waiting for the water in the teapot to get to the advised temperature for the type of green tea I had selected, I noticed some steam droplets, typically 3 to 10 μm in diameter, dancing above the teapot. Below one of the two pictures that I took. These droplets are not jumping from the boiling water, but are forming just above it due to the colder air around the teapot causing the water vapour to condense in small droplets. I guess that the shape of the teapot makes encourages colder air drawn from the sides due to the upwards flow of heated air with the water vapour.

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Saturday, March 14, 2026

AI Eyes

I went to see the exhibition FAI (Fine Art intelligence): 'AI Eyes' again, which I briefly visisted on Friday, February 28. It has works by a number of female photographers who used AI to modify some part of their work. Work from the following photografers was on display: Quite interesting.

Link

Friday, March 13, 2026

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Thursday, March 12, 2026

The China Labyrinth

In the past days, I worked on a JavaScript implementation of an Exact Cover problem solver, which can be found in the file ExactCover.js. I decided to test it with finding 'compact' solutions for The China Labyrinth as I did before on March 16, 2019. It generates a new random solution every four seconds.

This text is displayed if your browser does not support HTML5 Canvas.

Curly kail with celery root

Today, we made some curly kail and used both potatoes and about half of celery root. All these ingredients we received from the harvest of Herenboeren Usseler Es. This was the last curly kail, the heads of the plants, that we received for this year. This is the first time that we used celery root. We also added pork and spice mixture, and at it with gherkins and Rookworst, a type of Dutch sausage that is traditional served with several types of hotchpotch dishes.

Wednesday, March 11, 2026

Everyday Bridges

In the evening, I went to the opening of the exhibition Everyday Bridges with photographs by Maryam Rostampour at B93. The exhibition is about her project that she did in the past months where she looked at Enschede through the everyday lives of migrants. I read all the text with the photographs and I enjoyed talking with several people at the opening.

Links

Tuesday, March 10, 2026

Bring Your Own Beamer

From 19:00 till 23:00, I showed my animation at the Bring Your Own Beamer event at TETEM art space. This is the third time I joined this type of event. The previous time was in 2018. This time, I am showing an annimation based on irregular grids of squares and equilateral triangles and street tile patterns (once every four times). For the implementation of the later, I adapted and earlier program into the program STWangGen.cpp, which outputs all generated states into a JavaScript file that is used by the random generation function that I reimplemented in JavaScript from the C program. I also printed a QR code with the link to the animation and many people used it to view the animations on their phones. Quite a lot people asked how it worked. I also discovered some interesting 'analog' effects when unfocussing the projection. The other artist and/or instalations at this event (if I did not miss one) were: It was an intereting evening with a great variation of installation and projections.

Link

Monday, March 9, 2026

Links

Sunday, March 8, 2026

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Friday, March 6, 2026

19.6° Celsius

The temperature at Twente Airport has gone up to 19.6° Celsius, which breaks the previous record of 18.1°C on this date in 1989. In the city I saw some magnolia which already started to flower. I saw some pink and white spots at the top of some of the buds of our magnolia.

Link

Thursday, March 5, 2026

Temperature records

I wrote a program to generate a page with a list of daily temperature records since August 1981 (the year I came to live in Enschede) as recorded by the nearest official weather station at Twente Airport based on the file etmgeg_290.zip that can be downloaded from the website of the Royal Netherlands Meteorological Institute. Last Tuesday, the temperature reached 17.6°C at Twente Airport beating record 17.2°C from 1959 and today it reached 17.8°C breaking the record 15.6°C from 2013.

Link

Wednesday, March 4, 2026

Moon in the sky

This evening, I decided to biked to the care center where Andy lives to attend some meeting because the weather is quite nice with (near) record temperatures and clear skies. On the way going there, I followed some sign for the direction of Oldenzaal taking the road called Oldenzaalseveldweg, which took me into a forrest area (officialy closed after sunset) and resulted in some detour. The total trip was about 16.4 kilometer and took me 64 minutes. On the way back, I took a route along the main roads avoiding some short-cuts, which was about 16.1 kilometer and took me 67 minutes. The road from Losser to Enschede was rather dark except for the light of the moon, because it does not have street lights except near some road crossings. At 21:59, I took the picture shown below approximately matching this Street view image:

Image

Links

Monday, March 2, 2026

Itchy Boots

I have been following the YouTube channel Itchy Boots about the travels of Noraly for some months and I also started to track her biking routes in Google Earth and recording them in a KML file. She posts her videos on Sundays and Wednesdays. She just announced that they will be posted on Sundays only for the coming time. I guess that there are some troubles with the planning of her trip for the coming season. The videos she puts on are from a trip she made around August and September 2025. I am using Google My Maps to generate most of the tracks. It has an option to export tracks as KML/KMZ files. Her videos only cover short parts of her biking trips and it is not always possible to establish which route she took exactly. The current videos are about traveling throught China, which have complicated things a bit. On January 25, I already wrote about a program that I use to correct for the offset between the roads and the satelite images. For all the Chinese text, I have been using the Google Translate option for translating texts on images. I have been using the Chinese amap.com for finding locations with Chinese texts. It does not always works well, because signs on shops and restaurants usually do not contain names, but just state the type of shop it is. You can search for hotels, shops, and hospitals for example, just like with Google Maps. I also have not figures out if amap.com has an English mode and if so, how to enable it. The roads in Google Maps within China are often outdated or contain errors, causing it to generate incorrect routes, which require some editing in Google Earth. In the video of last Sunday, Heading deeper into the land of the DRAGON (unseen China) |S8, EP124, she and mister Bing, her (manditory) guide for traveling within Xinjiang, visit the shop (selling pig meat) of his grandfather-in-law because it happened to be along the route. The fragment starts at 6:39. Yesterday evening, I already spend a long time geolocating it, assuming that it was within the city limits of Hami, a large city along the route. According to the sign at the start of the road they enter, it must be near a hospital, because the sign talks about the area being a temporary parking locations for a hospital. I search for locations near hospitals and also for locations near "pig meat shops", but failed to find it. This evening, I discovered a location matching that is actually a bit to the west of the city in a small town. I also succeeded in finding the hotel they stayed at the end of the trip and the 'shopping' center with traditional Chinese looking buildings in the city of Balikun/Barköl, which is in Barkol Kazakh Autonomous County. I felt that Bing maps had beter satelite images for the city. The map in OpenStreetMap shows most of the roads, but only a few buildings, however, it does indicate the location of the remaining old city walls, which are not marked on any of the other maps. In other locations, I also saw the, sometimes barely visible, remanents of the Chinese wall. I have noticed that OpenStreetMap often does show trails that are not found on online road maps.

Links

Saturday, February 28, 2026

Sickhouse Warming (Day 2)

Today, I attended the second day of Sickhouse Warming. I primarily went there to watch movies and documentaries. I saw: I left the premises twice in between the screenings: One time to visit two bookshops in the city center and one time to go home for dinner.

Link

Friday, February 27, 2026

Sickhouse Warming(Day 1)

In the afternoon, I went to the opening of Sickhouse at their new location. They have organized the Overkill Festivals. Last year, there was no Overkill festival, because they had to evacuate the old location and were still refurbishing the new location, which we opened with a small festival today and tomorrow. Because I went into the city, I first went to see the exhibition FIA (Fine Art Intelligence) at photo gallery Objektief. At Sickhouse, I attended the afternoon panel talks.

Feminist media, Feminist practice

The first panel talk, the panel members first gave an introduction. Christie Morgran talked about Softer, a movement for softer digital futures. It is based in both Copenhagen and London. They also plan on having an event in Amsterdam, possibly with Valerie Fuchs. They had an online event with Mindy Sue along side the Soft Robot event that was held last week. Next Vanity Roxane talked about The Fem Dem that she started to empowering woman. She mentioned Open Source Radio, where they curate music, and Nieuwe Electronische Waar, as some of the things she was/is involved with. As the last panel member, Juliette Lizotte introduced herself. She is involved with Hackers & Designers in Amsterdam. She talked about two projects: Sisters of the Wind and Harri Kanta, which was shown on Overkill 2024. During the panel discussion, Christie remarked that she noted that technical tutorials, such as for example. for 3D modeling, are ofthe hyper masculine.

ALT-Tech for Alternative Futures

Roos Groothuizen calls herself a media artist who cares about human rights. She talked about a DIY alternative for digital doorbells that upload footage to servers and are used for surveillance. See instructions in English for building one. Pablo San Gregorio is a game designer, who has one of his creations in the exhibition, and an aspiring artefact artision. He wants to know how things do work and how they are made. Sunjoo Lee talked about her Electric Garden project that involves microbial fuel cells and one of the projects she did at Creative Coding Utrecht. Rein van de Woerd talked about permacomputing and about self hosted websites.

Finding, Building, Claiming our Space

In this panel Tessa Wiegenrinck (photographer), Alicia Breton Ferrer, (from Roodkapje Rotterdam), Marie Janin (from Sickhouse), and Jasper Schütz and Reinier (both from Studio Complex Enschede were asked questions about their art spaces.

Exhibition

In the exhibition at Sickhouse the following artworks, installations, and/or games were present:

I also saw the book Deep Simulator Ag in the 'library'.

Drift performance

Around 20:00, I watched the performance of Maggie Khorrami with her installation Drift, a sound and light interactive installation. During the performance she controlled the music with “RAGΞN", a wearable instrument — a body extension built with Conductive Rubber Cord Stretch Sensors that translates movement into sound. Interesting.

Link

Thursday, February 26, 2026

Crocuses

Below a picture of the crocuses in our front garden. They opened in the past days. Yesterday, there were record temperatures in the rest of the country. At Twente Airport the temperature went up to 16.7° Celcius, but that did not break the record from 2019 for this day. Today, the temperature went up to 17.4°, which does not break the record of 19.3° from 2019 for this day. It looks like spring has started with temperatures higher than normal.

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Tuesday, February 24, 2026

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Saturday, February 21, 2026

RSS feed

Someone asked if I did have RSS feed for my website. I extended my chkhtml.c program to generate an RSS file, the file: rss.xml, based on the information available on my home page. The descriptions with the items are generated from a comment starting with Descr: that are removed when the file is uploaded. All the items also need to have a GUID. First, I just generated random GUID's using the code found here. Then I decided to generate it fromt the link. I arrived at the following statement: 
	v = 12582917L * v + v % 12289 + ch;
The variable v is a 64-bit unsigned integer and for ch the next (cyclic) character of the link is used. The value of v is used for generating the next 'digit' of the GUID until all are generated. You could also view this as a hash function. I got the two prime numbers from good hash table primes.

Friday, February 20, 2026

Link

Thursday, February 19, 2026

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Wednesday, February 18, 2026

Books

At 16:04, I bought the following two books from Rataplan: At 16:28, I bought the following two books from Het Goed written by Frida Vogels in Dutch and published by G.A. van Oorschot B.V. for € 3.25 together: I already had seen these two books some weeks ago, but was not sure if I should buy them, because I do not know whether I will ever find the time to read them. I have not been reading a lot recently. I also do not know what is the added value of reading books, except for relaxation or killing time. I still can not resist the tempation to buy books and extend my book collection.

Link

Monday, February 16, 2026

Links

Sunday, February 15, 2026

2 cm snow

Yesterday, it was already on the news that we would get lots of snow today. During the night the temperature at Twente Airport dropped to -8.2° Celsius, which is rather cold for this time of the year. Today, the day started with a clear blue sky and a lot of sunshine causing the temperature to go up to 4.2° Later in the afternoon, she sky became more and more clouded. Around 20:00 in the evening, the temperature dropped to around zero and it started to snow. Around 22:00, I measured about 2 cm of snow on a surface about the ground. The ground was also covered with snow, but maybe not that high.

Saturday, February 14, 2026

Loving Art

I went into the city and went to see the exhibition Loving Art at Creative Broedplaats Enschede. The official opening is this evening at 19:00, but they opened at 14:00. I liked the following works: (I overlooked the work by Rosanne de Groot.) I talked a bit with some of the artist presesnt.

Friday, February 13, 2026

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Thursday, February 12, 2026

Links

Wednesday, February 11, 2026

Undertow

In the evening, I went to the opening of the exhibition Undertow with work by Judith Schepers at artist collective B93. It was an interesting exhibition. Some of the works are:

I took a postcard with a reproduction of Labyrinth, which shows a labyrinth with a key at the center between the underground roots of two trees standing close to each ohter, and a small button with the name Cas Klaver.

Monday, February 9, 2026

Polygons problems

A few days ago, I came across the article Any-Angle Flow Field Algorithm for Navigation on Reddit, which made me think about similar algorithms I worked on related to finding the shortest path between two points in a 2D plane that is limited by polygons on integer points. It made me also think about the Clipper2 - Polygon Clipping Offsetting & Triangulating library, which is used in many slicers for 3D printing. (The triangulation function is new to me, but it does not surprise me at all, because it is very close to the other functions.) Algorithms to combine polygons (to calculate the union, intersection or difference) have to calculate the point where two line segments cross. If the end points of the lines have integer coordinates this does not guarantee that the intersection also has integer values, because it involves a division and because a division only returns an integer when the numerator is a multiplicate of the denominator, which is often not the case. One solution is to 'round' the intersection to the closest point with integer values. This could change the area of the polygon. So, how to deal with this? One could define that two polygons are equivalent when they cover the same grid points (with integer values). With cover we mean, points that are either inside the polygon or on the polygon. In that case it is possible to construct a combination of two polygons, but it will probably increase the number of line segments that are needed. I fear that the algorithms to implement this is far from trivial to deal with all possible cases. It is easy to define which grid points should be included into a combination of two polygons, but if the number is large, it could be difficult to construct a small sets of line segments that enclose all those points. It is possible that a combination operation results in disconnected collections of points that require multiple polygons.

Friday, February 6, 2026

AI building a C compiler

Yesterday, Anthropic announced that they tasked Opus 4.6 using agent teams to build a C Compiler in Rust and it in two weeks and burning the equivalent of 20.000 USD in tokens produced a working compiler. I still believed that AI would not be able to write complex program such as compilers, but appearingly, I am wrong. I scanned through the repository, primarily read the documentation, which I presume was also generated, and discovered that it covers more of C than what I have implemented in my C compiler for replacing the GNU Mes compiler used in live-bootstrap. I should be noted that they did use a very large set of unit tests to let the AI generate code for. This is a kind of ideal situation, because in practice it hardly ever happen that such sets of unit tests are available when a new piece of software is available. There is a method called test-driven development (TDD) where you first write unit tests for each part of functionality you want to implement. So far, I have not really worked with AI agents, not believing in there usefulness, but now I think I should maybe look into it more. It will definitely have an impact on software development in the coming years.

Link

Thursday, February 5, 2026

GNU Mes replacement for x86

I am now at the point that I have a replacement for stage0 of live-bootstrap that does not depend on the GNU Mes compiler for the x86 target. On January 27, I had already shown that I had written a C-compiler that could compile the Tiny C Compiler version 0.9.26. In the past week, I got all other utilities that are needed to compile the Tiny C Compiler from the source files copying the structure that is used in live-bootstrap repository. In the future, I might make a clone of that repository with my alternative for stage0. With this, I have theoretically completed tasks 2, 3, and 4 of the project. I might still need some additional testing, fine-tuning, and documenting.

Tuesday, February 3, 2026

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Monday, February 2, 2026

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Saturday, January 31, 2026

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