Previous Up No next

Dairy, March 2019

Sun Mon Tue Wed Thu Fri Sat
                      1   2
  3   4   5   6   7   8   9
 10  11  12  13  14  15  16
 17  18  19  20  21  22  23
 24  25  26  27  28  29  30

Saturday, March 2, 2019

The naked truth

In the afternoon, I went to Rijksmuseum Twenthe for the exhibition De Naakte Waarheid (The Naked Truth. I found the following works notable (in the order I saw them):

Afterwards, I went into the city. At bookshop Broekhuis there was an exhibition with works by Jeanine Wubbels. I also went to photo gallary Objektief to see the exhibition MALE. HAIR. -3 by Rem van den Bosch.

Monday, March 3, 2019

Paarse Dag 2

This evening, I went to collect the art work Paarse Dag 2 made by Simone Zacharias, which I had first seen on Saturday, February 2. Again, a work with both figurative and abstract elements, just like most of the other works that I bought in recent years. It seems that purely abstract is too abstract for me. I also like the colours in this work, as purple ('Paars' in Dutch) is my favourite colour.

Wednesday, March 6, 2019


I went to the opening of the exhibition Colourtramp by Maria Britze at B93. I found her newest work, drawings made with colour pencils, the most interesting, and I was not the only one in that regard. I want to buy one of these drawings.

Saturday, March 9, 2019


At 15:58, I bought the book Science * Art written by Ans van Berkum and Tom Blekkenhorst in English and published by The Fentener van Vlissingen Fund, ISBN:9789090013596, from charity shop Het Goed for € 2.50.

Magnolia seed

This morning, I noticed that some of the outer shells of the flowers of our magnolia had cracked, a sign that it might start flowering within some weeks, which would be rather early this year. I decided to have a look at the one seed that I had discovered last year and kept in our shed, only to discover that it was covered with mold. In the afternoon, told Annabel about. She went to inspect the magnolia and discovered two other withered pods that had contain one or two seeds. Annabel noticed that it is not so difficult to grow a magnolia from a cutting. I told her, that I rather grow one from a seed. This fall, I will look more carefull for seeds and hopefully treat them better.

Friday, March 15, 2019

The China Labyrith

While thinking about better ways to solve the Octopuszle, I decided to take one of the diagonals away, and try to fit the 64 remaining pieces into a 8 by 8 grid. Even then, the program did not find many solutions per hour. I let the program run some time until it found 1900 solutions. I did think about some ideas to find more solutions. I did realize that the remaining puzzle was actually The China Labyrith inside a rhombus. After realizing this and remembering the statement: "It was soon discovered and proven that the number of seperate groups (the blank counting as one group) will always equal the number of loops (holes in the solution)", it became clear to me that one of my approaches to find more solutions, was never going to work. Also it is clear that the one piece with no lines, cannot be at the edge, but must always be in the middle. This evening, I worked at the visualization of one of the solutions, also to verify that my mapping to an exact cover was actually correct. The visualization uses one of the lines generated by the exact cover algorithm.

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

Saturday, March 16, 2019

Exhibitions and book

I went to XPO to see the exhibition A Blue, A Purple, Aloë vera, Aster, Banaan, Cupcake, Engeland, Hibiscus, Pilli Pilli, Prinsessen Roze, Selectie and Ultiem by Evangeline Clark. She was there herself and I talked a little with her. I think about buying Pilli Pilli. Next, I went to bookshop Broekhuis, where at 16:08:40, I bought the book De edele kunst van not giving a fuck written by Mark Manson, translated from the English The Subtle Art of Not Giving a F*ck into Dutch by Annoesjka Oostindiër and Henk Popken, published by Bruna Uitgevers in 2017, ISBN:9789400509023, for € 20.99. I walked through the city and went to have a look at the exhibition Monsterproject at Concordia. In a bookshelve, I discovered a copy of Jaarboek 09/10. I made some inquiries as to if it was on sale, but it was not. I did get some tip about another place where the AKI yearbooks can be found.

Octopuszle solutions

A large part of the day, I worked on a program to generate an exact cover problem for solving The China Labyrinth within a more compact, hexagon shaped, enclosure. As usual, a one off error, was the last bug that kept the program from running. Below one of the solutions is given.

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

I noticed how this solution consists of three parts (counting the empty piece as a separate part), and it only has one loop (circling the empty piece), which seems to be a counter example of the statement that I quoted yesterday. Maybe the proof is not as solid as it was thought. Because there are so many solutions to the puzzle, I thought that maybe an algorithm that would search for solutions at random would give a more varied number of solutions. When I started working on this, I discovered a bug in the algorithm, that was introduced when I did some experimentations on reducing while solving. When I fixed it, the program returned many solutions per second. I decided to also give it a try at Octopuszle and for that too it produced many more solutions than before. Below ten random solutions are given.

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

This months interesting links

Home | February 2019