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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, March 18, 2018


I decided to use to Boekweek gift to go to Amsterdam. I first went to bookshop Het Martyrium. At 13:05, I bought the book The Trip: Andy Warhol's Plastic Fantastic Cross-Country Adventure written by Deborah Davis in English and published by Simon and Schuster in 2015, ISBN:9781476703510, for € 9.95.

Next I visited the Stedelijk Museum. I went to see the exhibition The Collection: Stedelijk Base. I saw (among many others) the following works:

  • Kitchen Gardens on Montmartre, 1887, by Vincent van Gogh
  • La Montage Sainte-Victoire, ca 1888, by Paul Cézanne
  • Femme dans un paysage, 1890-92, by Anna Boch
  • Tableau no.3: Composition in Oval by Piet Mondriaan
  • Tableau III: Composition in Oval by Piet Mondriaan
  • Composition with Blue, Yellow, Red, Black, and Grey, 1923 by Piet Mondriaan
  • Composition with Yellow, Red, Black, and Grey, 1920. by Piet Mondriaan
  • Lozenge Composition with Two Lines, 1931, by Piet Mondriaan
  • Cathedra, 1951, by Barnett Newman
  • North Atlantic Light, 1977, by Willem de Kooning
  • Rosy-Fingered Down at Louse Point, 1963, by Willem de Kooning
  • Espaces Virtuels: Jaune et blanc, 1965, by Jesés Rafael Soto
  • R 62-16, 1962, by Jan Schoonhoven
  • Aggregration: One Thousand Boats Show, 1963 by Yayoi Kusama
  • Art Must Be Beautiful, Artist Must Be Beautiful, by Marina Abramovic (only the last minutes)
  • Windmolen, ca 1917, by Piet Mondriaan
  • Clothing material, 1964, unknown
  • 18A, Dec 02, 2002, 2002, by Peter Struycken
  • 023, Dec 02, 2002, 2002, by Peter Struycken
  • Radioaktiever Abfall, 1992, by Sigman Polke
  • The Extinction of Feeling (HAL 15/91), 1991, by Peter Halley
Next I saw the exhibitions:

At 14:58:09, I bought the book Art Sex Music written by Cosey Fanni Tutti in English and published by Faber & Faber in 2017, ISBN:9780571328529, from Buchhandlung Walther Koenig at the Stedelijke Museum for € 12.80.

Finally, I visited bookshop Scheltema for about one and half hour. I did not buy a book.

Saturday, March 17, 2018

Snow and cold

Yesterday there was some light snow during most of the afternoon, but it did not stay on the ground, because the temperatures were too high. This morning, there was some snow and some of it stayed on the ground. Temperatures are very low for the time of the year. Two weeks ago, we also had a cold period. In both cases the cause is the same: high pressure over Scandinavia that transports cold air from the polar region to us. The maximum temperature at 2m was -0.7° Celcsius and at 10cm it was -0.1° Celsius. It seems we have hit record low temperatures today.

Gigatron kit

This afternoon, I ordered a Gigatron kit. On Friday, December 8 last year, I went to a presentation about the Gigatron TTL Color Computer.

Thursday, March 15, 2018


At 20:24:37, I bought the book En liefde in mindere mate: dagboeken 1961-1987 written by Doeschka Meijsing in Dutch, edited by Ben Peperkamp and Annette Portegies, and published by Singel Uitgeverijen in 2016, ISBN:9789029539463, from bookshop Broekhuis for € 17.50. I got the book Gezien de feiten written by Griet Op de Beeck in Dutch and published by Stichting Collectieve Propaganda van het Nederlandse Boek in 2018, ISBN:9789059654334, for free as part of the Boekenweek. Coming Sunday, I can also use it to travel by train through the whole of the Netherlands.

Saturday, March 10, 2018


Wednesday, March 7, 2018


At 12:04:08, I bought the book Mirrored Years written by Yayoi Kusama, Diedrich Diederichsen, Midori Yamamura, and Lily van der Stokker, in English published by Museum Boijmans Van Beuningen in 2009, ISBN:9782840663126, from bookshop Broekhuis for € 13.95.

Tuesday, March 6, 2018

More results for 8

I started the program for sizes 8 and 9. For 8 it found five more solutions, besides the three already known solutions. All new solutions have a piece with size 105. The solutions are given below. I also verified that all earlier found solutions for 7 are included in the solutions that found yesterday.
6 9 10 21 25 36 41 49 56 64 69 71 84 95 99 105
6 9 21 25 26 36 41 49 56 64 69 71 79 84 99 105
1 10 14 25 29 41 44 49 56 61 64 76 79 91 95 105
4 11 25 26 31 41 44 46 59 61 64 74 76 79 94 105
1 14 25 29 34 41 44 49 56 61 64 71 76 79 91 105
2 17 25 32 37 38 47 52 53 58 67 68 73 80 88 103
11 25 26 29 31 41 44 46 59 61 64 74 76 79 80 94
17 23 25 32 37 38 47 52 53 58 67 68 73 80 82 88

Monday, March 5, 2018

More solutions for 7

In the evening, I worked on the program for the the Irregular Chocolate Bar puzzle and found more solutions for 7. Already some time ago, I started working on a version of the program that iterates over all partitions for a given size, such that the largest piece in each bucket is ordered from large to small and such that inside each bucket the pieces are also ordered from large to small. The idea is that by doing this, it is possible to avoid partitions that similar to an earlier partition except with respect of the order of the pieces. Furthermore, the algorithm has implemented a check to stop trying to construct a partition when in some bucket the pieces are getting too small for it being possible to divide the remaining buckets in the maximum number of pieces.

After I verified that this worked correct for sizes 5 and 6, I added a partial knapsack algorithm, to check if a partial partition (for a given size) could be used for all smaller divisions, in order to cut away large branches during the generation that will never lead to a solution. When I ran this on size 7, it found 210 solutions, which is much more than the 56 that I reported on August 19, last year. Of these 210 solutions, 146 contain a piece of size 60. This means that there are 64 solutions that do not contain a piece of size 60, which is 8 more than the earlier found 56 solutions. I still have to verified that all earlier found solutions are included in the solutions found today, to rule out an error in the latest algorithm. The first solution found (with a piece of size 60) is:

7 set:  1 3 8 9 13 19 23 33 37 47 51 57 59 60
4 buckets with 105:  51+13+33+8 60+3+23+19 59+9+37 1+57+47
5 buckets with 84:  57+19+8 51+33 60+1+23 47+37 59+3+9+13
6 buckets with 70:  59+3+8 51+19 37+33 47+23 57+13 60+1+9
7 buckets with 60:  33+19+8 37+23 47+13 51+9 57+3 59+1 60

Thursday, February 22, 2018

Focus on colour

In the evening, I attended the opening of the exhibition Focus on colour organized by FOTON. On a long wall there were many small pictures with dominant colours going from purple to blue to green to yellow to orange to red. And in the small room there were large black/white pictures. I found two them rather interesting. One of a thunderstorm and one of crossed legs, but taken in such a way that you do not immediately recognize which is which. Someone mentioned Edward Weston in this respect.

Wednesday, February 21, 2018

Repairing my Panasonic Lumix DMC-TZ8

This afternoon, when I wanted to take a picture with my Panasonic Lumix DMC-TZ8, I got a message that the DS card was locked. When I took it out, I discovered that lock mechanism was broken. I tried to fix it with some scotch tape, but it did not work and the SD card got stuck in the camera. I was slightly annoyed by this. This evening, I decided to open up the camera. I followed some instruction videos on YouTube and managed to open it up to the SD card reader (after I had removed the SD card with force). I also opened up the SD module itself, because I wanted to see if I could disable the mechanism that detects whether the card is locked or not. (I think it is really silly that there is a switch, because I want to use the SD card to take pictures, and not use to small screen of the camera to watch pictures on some SD card that is locked.) At some point, some part of the eject mechanism jump out of place and the string attached to it disappeared. The picture on the top right shows the camera in its disassembled state. The front and back pannels are outside of the picture. I spend almost an hour looking for it, but wonder, o wonder, I found it on the floor when I had already given up. (Actually, I already had seen it, but not concluded that it could not be it.) The spring is only about 1 cm long. I spend another hour trying to put everything together including a tiny piece of wood from a tooth picker to push down the lock detecting switch. After I had put everything together, I managed with some fiddling to get the camera working with the broken SD card. I only had one little screw left. I have some idea where it should have gone, but I decided not to bother taking the camera apart again.

Tuesday, February 20, 2018

Seven books

At 11:42, I bought the following seven books published by Witteveen+Bos from charity shop Het Goed for € 1.50 each:
  • Witteveen+Bos-prijs voor Kunst+Techniek 2005: Marnix de Nijs, witten in Dutch, published on November 10, 2005, ISBN:908077894X. About the price awarded to Marnix de Nijs.
  • Witteveen+Bos-prijs voor Kunst+Techniek 2006: John Körmeling, witten in Dutch, published on November 16, 2006, ISBN:9080778966. About the price awarded to John Körmeling.
  • Witteveen+Bos-prijs voor Kunst+Techniek 2007: Gerrit van Bakel, witten in Dutch, published on November 15, 2007, ISBN:9080778986. About the price awarded to Gerrit van Bakel.
  • Witteveen+Bos-prijs voor Kunst+Techniek 2008: Lawrence Malstaf, witten in Dutch, published on November 13, 2008, ISBN:9080778993. About the price awarded to Lawrence Malstaf.
  • Witteveen+Bos-prijs voor Kunst+Techniek 2009: Edwin van der Heide, witten in Dutch, published on November 12, 2009, ISBN:9789490335021. About the price awarded to Edwin van der Heide.
  • Witteveen+Bos-prijs voor Kunst+Techniek 2012: Angelo Vermeulen, written in Dutch and English, published on November 8, 2012, ISBN:9789490335052 About the price awarded to Angelo Vermeulen.
  • Witteveen+Bos-prijs voor Kunst+Techniek 2013: Driessens & Verstappen, written in Dutch and English, published on November 7, 2013, ISBN:9789490335069, About the price awarded to Driessens & Verstappen.


Sunday, February 18, 2018

Black Mirror

In the afternoon, I went to the opening of the exhibition Black Mirror with photographs by Jenny Boot at Fotogalerie Objektief in Enschede.

Saturday, February 17, 2018

Counting Digital Sheep

In the afternoon, I visited TETEM art space. I saw the new exhibition Counting Digital Sheep. Quite interesting. Especially code / coat by Jochem van Schip Artificial Dumpness, and Linger by Japser van Loenen. (Through the latter, I also found eps8266-sniffer when at home.) I also watched In the Robot Skies short film by Liam Young.

Tuesday, February 13, 2018


At 10:14:23, I bought the CD Interstellar: Original Motion Picture Soundtrack from bookshop Broekhuis for € 9.99.

Saturday, February 10, 2018

The MacMahon Squares

Yesterday, I read about Jigsaw Puzzles and The MacMahon Squares on I Programmer, and decided to give it a try. My first idea was to convert the problem to an Exact Cover problem. However, it did not find any solutions. This made me think about a program that could find the best almost solution. When I finished the program, it found 46 solutions. After some debugging, I found a bug in the algorithm to generate an Exact Cover and my Exact Cover solver found the 46 solutions with a second. I combined both algorithm is one program. The 46 solutions are given below:

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Friday, February 9, 2018


Wednesday, February 7, 2018

Natural well

For some week, there has been some water flowing across the bicycle path along the road called Hendrik Ter Kuilestraat at a location that I talked about before. This morning, I noticed that the water was coming from one spot and I stopped to take the picture shown on the right. You can just see the water flowing. A little further on the road, there are also some wet spots, which have turned into ice due to the low temperatures of the past days.


At 12:00, I bought the book following books from charity shop Het Goed:
  • Rijksaankopen: 1985 edited by Evelyn Beer, written in Dutch, and published by Rijksdienst Beeldende Kunst in 1986, ISBN:907146508X, for € 2.95.
  • Rijksaankopen 1987: werk van hedendaagse beeldende kunstenaars edited by Ruud Schenk, written in Dutch, and published by Rijksdienst Beeldende Kunst in 1988, ISBN:9789012059084, for € 2.95.
  • Made in Tilburg written by Caroline Boot in Dutch and published by Nederlands Textielmuseum in 2004, ISBN:9070962349, for € 2.95.
  • Doen jullie het nog?: seks en liefde in relaties written by Jean-Pierre van de Ven in Dutch and published by Ambo/Anthos B.V. in 2012, ISBN:9789026326585, for € 4.50.

150 year Broekhuis

At the end of the afternoon, I visited bookshop Broekhuis, which was established exactly 150 years ago. Five years ago, I bought a book when they celebrated their 145 years existence. The bookshop is still at the same location and has undergo some improvements in the past five years. I did not buy anything.

Friday, February 2, 2018

Bring Your Own Beamer

This evening, I attended the last Bring Your Own Beamer event at Tetem art space. The event was similar to last years. I occupied the same spot with an updated version of the project based on Street Tiling Patterns and a projection of a negative of an old picture of Li-Xia by the parts of the beamer that I put together last Tuesday and finished Wednesday evening. A picture of this is shown on the top right. For the Street Tiling Patterns project, I increased the speed of the animation and I removed a bug in the algorithm to find a matching pattern. There were some people from last year. One of them was Willemijn Calis. I also met Tessa Langeveld, who was showing moving forms in still spaces. A lot of people from TkkrLab came to visit and two of them had brought their own projects.

Before the visitors came at eight, I started working on the idea to pick the colours for the Street Tiling Patterns project from a limited palette as inspired by the colour palettes by Peter Struycken. At home, I continued working on this, resulting in the following palette:

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Tuesday, January 30, 2018

BYOB preperations

This evening, at TkkrLab, I spend some time preparing for coming Fridays "Bring Your Own Beamer" event. First I tested my notebook with a beamer to see if it worked with the updated version that I showed on last years event. Basically, I have made it run faster, because it was changing to slow to be noticed by people just giving it a short look, and I fixed a bug, which prevented one of the effects not to work properly. Next I played with some parts of an old beamer, which I found on January 24, 2017. Some other member told me that he still had the lens to go with it and showed where it fit, which made me realize that I was totally wrong about how it worked. At some point, because I did not have the right lamp, I decided to leave it for home and work a little on my notebook. At home, I did some further experimentation and got some idea of how I am going to use it.

Monday, January 29, 2018


March 2018
February 2018
February 2018
January 2018
December 2017
November 2017
Alzheimer's Disease
Trip to China 2010
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