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Diary, September 2019

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Sunday, September 1, 2019

18 vectors

Yesterday, while guarding the entrance for the retro game day, I looked at the problem of finding at the 35 vectors. I have been looking at finding collections of eighteen vectors at the Haming distance of four from a vector. The reason why there are eighteen is because there are only six ways to change two of the four zeros into ones and at most three non-overlapping pairs of ones that are changed into zeroes. I realized that there are some restrictions as to how for three patterns of zeros that are changed into ones that only differ at two locations, such as for example, 1100, 1010, and 0110, the way the ones are changed into zeros must all be different. Because if they are the same, the Haming distance is only two. I got the idea that there were only four configurations, not counting all kinds of symmetries. But when I was at home, I wrote a program, which produced 19 solutions. Which meant that either I was wrong or the program. Today, I wrote the following animation to display the 19 solutions. The three colours refer to the three ways in which zeros are changed into ones and the three lines refer to the patterns in which the ones are changed into zeros. Any of the 21 possible lines cannot have two colours and there cannot be a point where to lines of the same colour meet.

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In the evening, I realized how there eight combinations of three vectors, such as in the example, and that these can be visualized as the triangles of the octahedron. And also that each edge represents the lines of two colours and that there are only three possible patterns of these, namely, where the lines are a cycle of six lines, a cycle of four lines and a path of two lines, or a path of six lines. This put a lot of restrictions on how the various patterns can be placed on the octohedron, and that that is a good way to determine all unique (with respect to symmetries) combinations of 18 vectors there are.

Wednesday, September 4, 2019


Today, my mother became a great-grandmother, because the oldest son of my youngest sister became a father. It also means that I have become a granduncle.

Thursday, September 5, 2019

Rainbow at Gogbot

While waiting with some other volunteers for the introduction tour along all the locations of the Gogbot festival, we saw a rather bright, double, and complete (as far as I could see) rainbow. I took several pictures, one of which is shown to the right. After the opening, at eight, I helped out as a guard in the Grote Kerk because there were a lot of visitors. I stood near the entrance, close to The Mictobial Vending Machine by Emma van de Leest, one of the few artist being present at the exhibition in this location and explaining her project to visitors. Also close were the Pink Chicken Project, Al¿ve, and Caravel. There was not much interaction or moving projects as in some of the previous years and several vistors commented about this to me while leaving the venue. At eleven, after the exhibition closed, I went to the Metropool concert room to have a peek at the Gogbot lift off // Experimental Electronics & Modular Night, which was free for volunteers, only to discover that they had very strict rules with respect to bags and coats, and that the small lockers costed two Euro each. I was a little disappointed, because I had hoped to work a little on my notebook while listening to the music, and decided to go home.

Friday, September 6, 2019


I was a guard at the former VVV-building. The first half on the second floor and the second half on the third floor. These floors had all the Young Blood nominees, selected from the graduates of the various art academics in the Netherlands. I found the following nominees mentionable (roughly in the order I encountered them at the exhibition):

The building also had the projects by the freshman students of the Creative Technology major of the University of Twente. I used the Embry-o-'matic to 'create' a designer embryo from Stork Industries. Mine was #10293 and I had to 'pay' $4929. In the evening, I again, helped out at the Oude Kerk, because some volunteers wanted to have dinner and one did not show up (or left early).

Tuesday, September 10, 2019

1773 constellation

I continued working on the 18 vectors problem (which is related to the KABK wrapping paper) and this evening, I worked on a program to calculate the number of unique ways the octahedron can be tilled with the 19 patterns I found on September 1. I arrived at a program which calculates in how many ways the edges can be marked with on of the three possible patterns, such that they are compatible with the 19 patterns. Such a 'constellation' does not neccessary match a solution of the patterns and even if it does, there could more than one. The program found 1773 such constellations. When at home, I thought about a different approach for finding the solutions for the 18 vectors problem.

Wednesday, September 11, 2019


I recieved the book Kilo-Girls written by Julia Luteijn in English, which I bought from the author for € 13.90 (including postages).

Saturday, September 14, 2019


I went to Tetem art space to look at the exhibition Xenobodies in Mutation. At the Exploring-Lab some people were assembling a small motor powered by solar cells. I also joined and assembled one.

Sunday, September 15, 2019

54718 solutions

I continued working on the program to calculate the number of different solutions of 18 constant weigh vectors 'around' a vector with seven ones and four zeros, where around means at a Haming distances of four and such that all vectors are at distance of at least four. The program found 54718 different solutions taking in consideration all possible permutations of the 'rows' of the vectors.

Monday, September 16, 2019


At 17:43, I bought the book What Do Women Want?: Adventures in the Science of Female Desire written by Daniel Bergner, in English, and published by Canongate in 2013, ISBN:9781782112563, from charity shop Het Goed for € 1.95.

This months interesting links

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