Dutch / Nederlands
Site map

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.

Tuesday, July 16, 2019

Apollo 11

Today, it is 50 years ago that Apollo 11 was launced. It was on a Wednesday and at 14:32 local time in the Netherlands. It is possible that I saw the launch live and otherwise, I must have seen later on the day. This afternoon, I watched the launch at Apollo 11 in Real Time.

1 year Peter Struycken

I recieved the publication 1 jaar Peter Struycken aan de Rijksuniversiteit Utrecht = 1 year Peter Struycken at the University of Utrecht written by Peter Struycken, Cor Blok, Rudi Fuchs, Ober A. de Vries, and A. Veen, written in Dutch and English, and published by Rijksuniversiteit Utrecht in 1971 from Aquilabooks for € 15.00. It is a collection of seven envelops, held together with metal spring file clip, of which five are filled with some writing of each of the authors. There are also some loose sheets containing the introduction. I am quite happy with it, because it is a rare item, which I saw only one time before, on Saturday, January 19, 2013 in the library of Stedelijk Museum.

Thursday, July 11, 2019

De Fundatie

Peter Struycken invited me to join him visiting museum De Fundatie in Zwolle and Heino. He wanted to see the exhibition Charlotte van Pallandt - Art as one's purpose in life about the work and life of Charlotte van Pallandt, who was one of the first artist he met and with whom he stayed in contact for the rest of her life. He thought, I would like the exhibition Michael Triegel - Discordia concors, the first exhibition of the works of Michael Triegel in the Netherlands. It is always a pleasure to visit some place with Peter Struycken, because he opens my eyes through his unique way of looking at art and the worlds.

From the exhibition about Charlotte van Pallandt, I found the following works worth mentioning:

  • Liggend naakt, about 1926.
  • Femie, 1929, teak.
  • Tors, 1940, teak.
  • Zittend vrouwelijk naakt, 1926.
  • Lopend meisje, 2007, by E. Siepman van den Berg.
  • Wilhelmina.
  • Constructie voor zelfportret / Structure for self-portrait, 1971.

From the exhibition about Michael Triegel, I found the following works worth mentioning:

  • Lucia, 2012.
  • Persephone und orpheus, 2012.
  • Ein Auferstehung, 2006.
  • Deus Absconditus, 2013.
  • Schafende Ariandne (kleine fassung), 2010.
  • Schafende Ariandne, 2010.
  • Auferstehung, 2002.
  • Sokrates, 2019.
  • Tenebrae, 2018.
  • Allegorie de Wahrheit, 2012.
  • Am Kreuz (Grosse Version), 2008.
  • Selbstporträt, 2016.
  • Porträt Kerstin, 2012.
  • Discordia Concors, 2018.
  • Paragone, 2014
  • Die Perser IV, 2018.

Other art works, that I found worth mentioning:

  • Losing grip by Gerlinde Visscher.
  • Finely Together by Ursula van de Bunte.
  • Color Waves by Jan van Bemmel.
  • Papillons by Francis Picabia.
  • De Molen 'Le blute fin' by Vincent van Gogh, 1886.
  • Wolken en Water by Turner, 1840.
  • Sluizen bij Katwijk by Jan Toorop, 1898.
  • Rij van elf populieren in rood, geel, blauw en groen by Piet Mondriaan, 1908.
  • Landschap bij de Butte Mont Martre (Paris) by Georges Michel, 1930-40.
  • Landschaftspark by Wilma Wijnen.
  • Seven Deadly Sins under Seven Jars by Ro-Nalt Schrauwen.
  • Europa heel divers by Jeanne van Bragt-Peijen.
  • 36 Europeanen by Henk Bakker.
  • The Marriage by Erikjan Koopmans.
  • Groot Zomerlandschap by Henk Chabot.
  • Havengezicht by Willem Parels, 1901.
  • Graphic Novels by Pjotr Müller.
  • Liggend naakt by Leo Gestel, 1909.
  • Compositie 1918, No. 5 by Bart van der Leck.
  • Vrouwenportret by Isaac Israels, 1910.
  • Monogram / Ronde Vorm by Hedwig Zweerus-Weber, 1975.
  • Rawsome! by Ronald A. Westerhuis, 2011.
At 16:43:33, I bought the book Charlotte van Pallandt: kunst als levensdoel written by Maarten Jager, edited by Ingrid Renkers, written in Dutch, and published by Waanders & De Kunst in 2019, ISBN:9789462622364, from Museum De Fundatie for € 22.50.

Sunday, July 7, 2019

Royal Academy of Art Finals

I went to the Graduation 2019 exhibition at Royal Academy of Art in The Hague. I found the following graduates noteworth (in the order that I encountered them or their works):
  • Marsha Wichers with Project Face Design.
  • Sunna Svavardóttir with her To Weigh installation.
  • Sophia Bulgakova with her Inevitable Blue installation, which was an interesting experience.
  • Jean-Baptiste Castel with Camera.1
  • Alexander Webber who created some bath bombs.
  • Natalia Vish with Nothing Exists when Nothing Happens
  • Matthew Lanning with a work which makes use of Lego bricks.
  • Ana Oosting with her Tomopteris Micans installation, which makes use of reflective materials, such that each observer with a head light will see a different image at the same time.
  • Rambhasiri Devakula with her thesis Subverting Submission: Reframing Asian Women in the Colonial Gaze
  • Jesús Canuto Iglesias with Nada Nuevo composition performed by step motors attached to steel plates and a steel bench.
  • Leon Wezenberg with One screw to rule them all on the development of a screw for a mission to mars.
  • Zoë d'Hont with Even the moon borrows its light from the sun, a rather successful attempt to create a Zen garden and meditation room with modern materials in an inside room. At the end of the exhibition, I went back to the room to meditate for some to process all the impressions I got from this day.
  • Thea Frommenwiler with Coral Protection Factor, a workshop on creating sun screen oil that is safe for coral reefs.
  • Zikko Assink with Pixels of water.
  • Stefano Zucchini with Untitles Frequencies IV
  • Hyo Young (Moe) Kim with 2xL, a carpet with glowing fibers.
  • Emma Sarpaniemi
  • Jill Louise Verweijen with #R.I.P., a project about alternative couffins.
  • Pien Post with a two legged chair that can only be used with a table.
  • Tijs Struijk with Club Folk
  • Sophia Wester with a large collection of drawings of receipts.
  • Risto Kujanpää with Hemisphere, about a Noric typeface.
  • Artúr Andrási with the game I could argue with that.

Saturday, July 6, 2019

Gerrit Rietveld Academie Finals

I went Amsterdam. Before going to the finals exhibition at the Gerrit Rietvel Academie, I first brought a short visit to bookshop Matrium. At the exhibition, I found the following things noteworthy (in the order, I encountered them):
  • Qianfu Ye with the documentary Mice of Rietveld
  • Moa Holgersson and Isadora Tomasi who did the SOUL HOLE pt 1 performance at noon.
  • Wietske Joan with an interesting installation consting of a kind of inverted disco-bal made of larger pieces of mirror that projected moving spots of light on the wall. On the wall there were green and blue patches, that matched the spots at certain moments, causing them all to light up at the same moment. At 12:25 I bought the book from her for € 10.00.
  • Guilio Angeli with Fossile Mary made out of many layers of carton cut with a laser cutter.
  • Fieke Ruitinga with a book with pencil drawings.
  • Raven Opal Amber Kiss with Intimate Immensity
  • Leja Valva Verheus with a study on different kinds of white space used in typography.
  • Éloïse Dieutegard with an installation with drops falling on a kind of dish and the sound being amplified.
  • Garzaro Enrico with pictures made with self made cameras with lenses made of glass lumps and experimenting with extreme long exposure times.
  • Marlies Werkelbach with HzO 5-115Hz.
  • Victoire Eouzan with a book with pictures called When the mountain took the place of my father.
  • Veronika Vidø with Inside me.
  • Qiteng Wu with a performance.
  • Marius van Zandwijk with a colourfull carpet depicting the results of a psychology test he took.
  • Pieter Meijer with an L-shaped piece of wall that could be moved over the floor together with a virtual simulator.
  • Pauline Rip with sadles for riding ghost animals whoes properties were exactly established by cryptozoologists.
  • Keyfa Park with Radio-Orientation
  • Cem Berendsen with the film A Model of the Tides.
  • Tjacco Bakker with Taciturn
  • Jeanne Viviès with the book Everything I know. At 15:05, I bought a copy of the book from her.

Afterwards, I went back to bookshop Het Martyrium, where at 16:07:50, I bought the book Roekeloos written by Chrissie Hynde, translated to Dutch, and published by Nijgh & Van Ditmar in 2015 translated from Reckless. my life as a pretender written in English, ISBN:9789038801407, for € 8.00. I also discovered that De Slegte opened a shop again. I wnet in to have a look. At last I visited bookshop Scheltema, but did not buy any books.

Firday, July 5, 2019

Wild orchides

Thursday, July 4, 2019


Last night between 3 and 5 o'clock, the temperature dropped to -1.6°C at Airport Twente weather station at ground level (10cm above ground). Which is rather unusual for this time of the year, but must be due to clear sky and that the weather station is in open fields. It is the only place in the Netherlands where the temperature dropped that low.

Lost Energy

I went to the opening of the exhibition Lost Energy at Tetem art space. The exhibition is about the energy transition. Reinier Kranendonk started with a project about energy addiction. Françoise Braun and Casper Teijgeler asked people about things they bought but not really need. This exhibition will also travel to other locations. The third work in the exhibition is by Elise Leusink. The build an installation to show how much energy it cost to make a small piece of plastic. There will also a video made by students from the University of Twente with some research they did. Anabella Meijer is a comedian and wrote about energy transition: First Help with Climate Chnage. She calls herself a visual consultant, meaning that the makes drawings. She is also climate activist. She discovered that climate change is often talked about in negative terms and not in positive terms. She states that what makes us really happy also is good for the climate.

Wednesday, July 3, 2019

Difficulty versus number of solutions

I decided to investigate the relationship between the difficulty versus the number of solutions of the set of Fractal Jigsaw puzzles that Annabel has made. The difficulty is determined by the average number of steps to solve a puzzle using an optimal strategy, where a step is either the placement or removal of a piece (more). The image on the right shows the result using a linear scale. From left-to-right is the difficulty and from top-to-bottom the number of solutions. As expected there are not many puzzles that have both a high number of solutions and that are very difficult. This image is a little skewed because there are far more puzzles with fewer solutions than with many solutions and similar, many more that are easy than difficult. To compensate for this, I created a table where the puzzles are divided (for both dimension) into ten groups with respect to increasing number of solutions and increasing difficulty. This resulted in the following table, which is rather uniform, except for the numbers in the bottom right corner (as expected). The table also contains the size of groups.

          |  27  36  46  56  67  80 101 137 198 903
          | 253 243 260 247 261 244 262 251 254 253
   1  397 |  42  32  29  31  33  27  43  46  46  68
   2  272 |  28  15  20  23  20  22  22  35  47  40
   3  197 |  22  15  18  18  11  17  20  30  22  24
   4  163 |  13  14  14  17  20  21  10  13  19  22
   6  217 |  16  23  28  15  18  22  24  22  24  25
  10  305 |  25  33  28  27  37  35  27  28  29  36
  16  229 |  21  22  27  24  25  26  28  20  21  15
  26  249 |  20  29  24  38  26  27  32  26  18   9
  54  249 |  19  25  38  25  33  27  32  20  19  11
 798  250 |  47  35  34  29  38  20  24  11   9   3


Tuesday, July 2, 2019

Mysterious sign

Last Friday, I took a picture of the 'mysterious' sign with the installation of Faida El-Shoura. There are seven statements starting with the word "Possibility". The first two speak for themselves. The third has text '[  ]', which in some programming languages stands for an empty list or matrix. The fourth has the first 11 digits of π, as displayed by Google when you search for 'pi'. The fifth mentions Chand Baori, Tenochtitlan, the blue planet HD 189733 b, which is rather hostile, and an expression with 1215.67Å, which seems to be taken from Lyman-alpha emitter, which are far aways galaxies, whoes distance can be determined through the redshift of a the Lyman-alpha emission line of hydrogen. The sixth mentions the silver ratio and the French translation of "Wavelength understood by touch." The seventh has the Russian translation of "electrocution from breathing." This is followed by the text "Input" followed by 3 by 3 matrix, the text "Output" followed by 1, and an endless point definition. It seems like part of a script, possible, the script that is being used to generate the sound for the installation. I am not sure what it all means.

Monday, July 1, 2019

Finals 2019: Second visit

At the end of the afternoon, I visited the exhibition for a second time. I had a short talk with Faida El-Shoura. She told me that the mysterious print on the wall has some meaning. I met Tom van Veen and bought a copy of his book Pittu, een fragment

Sunday, June 30, 2019


Saturday, June 29, 2019

Warmth record

Today, at Airport Twente a new warmth record for this date was broken with 32.8°C. The previous record was 32.3°C from 1957. In many parts of Europe warmth records were broken.

Friday, June 28, 2019

Finals 2019

This afternoon, I went to the AKI finals 2019 exhibition at the AKI building. I found the works of the following graduated students noteworthy (in the order I encountered them):

At 18:38, I bought the catalog Developments 18/19 edited by Johan Visser, written in Dutch and English, and published by AKI Academy of Art & Design on Friday, June 28, 2019, ISBN:9789075522402, for € 10.00.

Tuesday, June 25, 2019

Hardest Fractal Jigsaw

During the night, I let the program run over all of the possible puzzles (with pieces up to size five) for just one second, to discover what might be the hardest Fractal Jigsaw puzzle. The running time was 1 second. Then in the morning, I ran the top ten with half a minute runing time. This resulted in:

  1336   2,2,2,2,2,2,2,2,3,3,3,4,14,15
  1229   2,2,2,4,4,4,9,9,12,14,15,999
  1173   2,2,2,2,2,2,2,3,3,3,3,3,3,4,9,999
   981   2,2,2,2,2,4,4,4,8,9,9,18,999
   954   2,2,2,2,2,2,2,2,3,4,4,9,142,999
   944   2,2,2,2,2,2,2,2,3,3,3,3,4,38,999
   928   2,2,2,2,4,4,4,9,12,18,38,999
   913   2,2,2,2,2,2,2,3,3,3,3,4,9,34
   838   2,2,2,2,2,2,3,3,3,3,3,4,12,14,999
   832   2,2,2,2,2,2,2,2,3,3,3,3,4,4,9

It is suprisingly, how many of these have the 999 piece, which is the smallest possible piece. In the evening, I also looked for the easiest and hardest puzzles that can be made with the pieces of the first series that Annabel made. The hardest is 2,2,2,2,2,2,3,3,3,3,3,4,12,14,999 in the above table. Some of the easiest are:

  13.0  2,2,2,3,4,7,14,14,34,38,999
  13.0  2,2,2,3,3,4,12,14,14,33,34
  13.1  2,2,2,2,3,3,14,14,15,33,34
  13.4  2,2,2,4,10,13,14,15,33,34,999
  13.5  2,2,2,2,3,3,3,4,13,14,33,34
  13.6  2,2,2,3,4,12,14,14,34,38,999


Today, the temperature reached 25.3°C at Airport Twente. This is the first time that the temperature reached this high this year and probably also on this date since the temperature is measured at this location.

Monday, June 24, 2019

Exact Cover complexity

When playing with the puzzles Annabel created, I discovered that the puzzle that I thought was the most difficult, because it had only one solutions and lots of pieces, was actually rather simple. So, this made me think about the complexity of an exact cover. Assuming that you have some strategy for solving an exact cover, you can count how many steps it takes on average to find a solution. Because with the puzzles, some pieces with the same shape can occur more than once, I decided to implement an exact N cover algorithm, where for each position (column) you can define how many 1's it should exactly contain. Each such exact N cover can be rewritten into an exact cover by adding some extra positions (columns) and vectors (rows). After having verified the exact N cover implementation, I implemented an algorithm that uses some randomness to find a solution. The strategy it uses is to find all positions with a minimal number of vectors to be selected and than at randomly select one of the vectors that is involved, taking into account that a vector could be involved with multiple minimal positions. Futhermore, I decided to both counting the placement and the removal of a vector as a step. This algorithm is called repeatedly within a fixed time interval, to find an average. For the puzzles from the first series, the results are presented below. The first column is the name of the puzzle. The second column gives the number of solutions to the puzzle. The third column gives the average number of steps needed to solve the puzzle when running the algorith for 10 minutes. The fourth column gives the pieces that make up the puzzle. The results seems to imply that there is no relation to the number of solutions to a puzzle and the difficulty.

  S1P1  123  36.9   2,2,2,2,3,4,7,9,14,14,34,999
  S1P2   68  68.0   2,2,2,3,4,4,7,9,12,14,34,999
  S1P3   18  34.0   2,2,2,2,3,4,4,7,14,34,38
  S1P4    8  35.6   2,2,2,2,3,4,13,14,15,33,34
  S1P5    3  84.5   2,2,2,3,4,4,8,9,14,15,34
  S1P6    1  22.5   2,2,2,2,3,3,3,3,4,4,12,14,33
  S1P7    1  24.2   2,2,2,2,3,3,3,4,4,4,7,10,14
  S1P8    1  28.8   2,2,2,2,2,2,3,3,3,3,3,3,4,4,5


Sunday, June 23, 2019


I first went to open day at 'De Zesprong', only to discover that it was offically already over. I met some people that I knew, including Femke Kloppenburg and René Völker. Next I went to XPO to see the exhibition A State of Obscurity by I-Yen Chen. She is from Taiwan. Next, I went to the opening of The Big Discovery at photo gallary Objektief with works from first year students from Cross Media from the AKI. I liked the following works:
  • The photo essay Lola by Yentil Foks.
  • The photo essay Zondag is voor de familie by Maxime Roelink.
  • The photo essay Lijnen by Koosje van de Lecq.
  • The photo essay Samen spelen, samen delen (as a booklet) by Christy Lugtenberg.
  • The wedding of Harry and Anne Ros (as a booklet) by Dione Ros.
  • Ik wil mijn broertje opnieuw in elkaar zetten by Emma Dekens.
  • Composities by Wouter Hof.
  • Cirkel by Iris Veltman. (I indicated interest in buying one of her prints.)
  • Restless Peace (a series of prints tranfered to a long sheet of paper) by Ralph van Westen.
  • Pa ken jij Niek? by Gaby van der Hertog, Christy Lugtenberg, and Yvanca van Veen.


Saturday, June 22, 2019


Friday, June 21, 2019


At 17:24, I bought the book The Te of Piglet written by Benjamin Hoff in English, illustrations by E.H. Shephard, and published by Mandarin in 1993, ISBN:9780749315146, from charity shop Het Goed for € 0.95.

Tuesday, June 18, 2019


At 17:48, I bought the book Art in the office: ING art collection, a universal language written by Consuelo Fernandez-Ruiz in Dutch, published by Waanders in 2006, ISBN:9789040083204, from charity shop Het Goed for € 1.95.

Monday, June 17, 2019

Puzzles by Annabel

In the past months, Annabel developed a set of eight fractal jigsaw puzzles. Today, she launched her website where they can be ordered separately or combined.


Friday, June 14, 2019

Powers continued

Yesterday evening, I had a look at how the expressions of the powers of (a2 + b2) are related to each other and I arrived at this figure:

   - +
  2   1
   \ + -
    1   2
   - + - +
  2   1   3
   \ + - + -
    1   2   3
   - + - + - +
  2   1   3   4
   \ + - + - + -
    1   2   3   4
   - + - + - + - +
  2   1   3   4   5
   \ + - + - + - + -
    1   2   3   4   5
The numbers in each line, stand for the equations and the '+' and the '-' symbols stand for the variant of the Brahmagupta-Fibonacci identity that has been choosen. The '\' is used when both '+' and '-' return the same result. This happens when one of the squares is zero. If seems that twice taking the same variant, leads to the same result. Lets see if this is generally the case:

(r2 + s2)(a2 + b2) = (rb + sa)2 + (ra - sb)2
((rb + sa)2 + (ra - sb)2)(a2 + b2) = ((rb + sa)b + (ra - sb)a)2 + ((rb + sa)a - (ra - sb)b)2 = (rb2 + sab + ra2 - sab)2 + (rab + sa2 - rab + sb2)2 = (r(a2 + b2))2 + (s(a2+ b2))2

(r2 + s2)(a2 + b2) = (rb - sa)2 + (ra + sb)2
((rb - sa)2 + (ra + sb)2)(a2 + b2) = ((rb - sa)b - (ra + sb)a)2 + ((rb - sa)a + (ra + sb)b)2 = (rb2 - sab - ra2 - sba)2 + (rab - sa2 + rab + sb2)2 = (rb2 - 2sab - ra2)2 + (sb2 + 2rab - sa2)2

Now, it seems that the results are not the same.

Sonic DIY

I the evening, I went to the second edition of Sonic DIY at Sickhouse in Enschede. First Patrick Jonkman gave a presentation about the history of electronic instruments. This was followed by a live performance by Dennis van Tilburg (on SoundCloud). Nicolas from soundforce told something about the Eurorack modules he is developing. It was mostly about a DCO (digital voltage controlled oscilator). After a short break, there were some five minute jam sessions with pairs of people. The jam was hosted by Gijs van Ouwerkerk with Ingmar Kops, Gregor Beyerle, Nicolas Toussaint, and Jasper Schütz. I listened to the first jam, but left the room when it became a little too hot for my tasted. I joined the Live Hex workshop held by Ole Nieling, which was about building a simple oscilator with the CD40106BE, also known as the Hex Schmitt Trigger (with inverter) IC. I build the basic circuit with a LDR and 10nF capacitor. I went on to experiment a little and put two oscilators in series using another 10nF capacitor. There were three more performances:
  • Hmisu in the main room using two synthesizers.
  • Acheface in the smaller room on a large Eurorack modular synthesizer. I danced during most of the performance.
  • Jungle of Wires in the main room with a rather small Eurorack modular synthesizer.

Sunday, June 9, 2019


July 2019
June 2019
May 2019
April 2019
March 2019
February 2019
Alzheimer's Disease
-- contact --




Art works
Useless lists


My life as a hacker
Signature programs
Software enginering
The Art of Programming
eXtreme Programming Programs


Hamilton cycles
cutting sticks
Califlower fractal


Volcano Blog


The email address below, may only be used for private communications. This email address may not be put on any mailing list. I do not want to receive emails with advertisements of any kind. My email address is:

Privacy statement

This is a static website with no contact form and no way to add comments. It has no advertisements and no trackers. It does not use cookies. I am not using any method to analyse traffic to this website nor keeping any logs. I am not collecting personal data besides what is published on this website. If you want me to remove any personal data (including your name or link to your website), please contact me by above email address and I will make all effort to remove the data as soon as possible. I am private person and this website does not serve any economic purpose. All cost for maintenance are paid by myself. I do not receive any payments. The website is ad-free and does not have sponsored links.

Site statistics

If I did not count wrong, this site consists of 966 HTML-files with a total size of 22,415,949 characters, having 47,296 internal links and 10,950 external links to (more than) 3,714 websites. (At least 731 of the external links are broken.) Furthermore, it contains 209 C/C++ program files with a total size of 4,710,094 characters, and 3 PASCAL program files with a total size of 35,259 characters. There are 74 text files with a total size of 784,772 characters. With respect to images, this site containts 1250 JPEG images (total size 54,629,524 bytes), 146 GIF images (total size 3,765,046 bytes), 93 PNG images (total size 2,256,174 bytes), and 2 BMP images (total size 3,727 bytes). With respect to sounds, it contains 14 WAV files with a total size of 389,002 bytes and 1 MP3 files with a total size of 70,182 bytes. It also contains 43 PostScript files (total size 308,387 bytes), 2 LaTeX files (total size 132,020 characters), 8 PDF files (total size 640,573 characters), 22 zip files (total size 2,487,335 bytes), 3 gzipped tar files (total size 52,345 bytes), 45 SGF files with a total size of 85,019 bytes, 103 KML files with a total size of 4,332,209 bytes, and 2 EXE files with a total size of 38,340 bytes. It also uses 15 JavaScript files with a total size of 659,809 bytes, This leads to a total size of 101,169,508 bytes.


Creative Commons License

I, Frans hold the copyrights of this and all other pages on this website. For this website a Creative Commons License is applicable. You may not use this work for commercial purposes. I consider all computer programs to be copyrighted by me under the GNU General Public License, unless stated explicitly otherwise. All quotes (text and program fragments) from other sources are excluded from this, and should be considered as copyrighted by their authors.

(This space is intentionially left empty)