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Diary, May 2018

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Tuesday, May 1, 2018

428,362 sets of equations

I calculated that there are 428,362 sets of equations for the the Irregular Chocolate Bar problem for the problem of finding 22 unique integers which can be divided in up to and including 10 partitions. (This calculation took 13 hours 39 minutes.) So far, my program has searched 62,378 of these sets of equations and found 959 solution with some duplicates resulting in 554 unique solutions. It looks like the program will require some more months to search the remaining sets of equations.

Thursday, May 3, 2018

Three Dune Books

At 09:49, I bought the following three book from charity shop Het Goed, for € 0.95 each, all written in English and published by New English Library:

I have now all books of the Dune series written by Frank Herbert both in English as in Dutch. I have not read all of them in both languages.

Monday, May 7, 2018


This afternoon, I bought a print of the woodcut 'Droomkoppel' from Willemijn Calis, which I saw on April 14 at the exhibition 'China Dreams'.

Wednesday, May 9, 2018


At 9:52, I bought the following two books from charity shop Het Goed: At 17:10, I bought the following seven comics (all in Dutch) from Valérian and Laureline series, drawn by Jean-Claude Mézières after a scenario by Pierre Christin, and published by Dargaud:

Saturday, May 19, 2018

Dairies of Doeschka Meijsing

I finished reading the book En liefde in mindere mate: dagboeken 1961-1987 about the diaries of Doeschka Meijsing, a Dutch novelist. This is part one, as she died in 2012. It seems that the second part has not been published yet. Almost half of the book consists of notes. Some of the notes, contain back ground information that is not really relevant for understanding the diary. The editors of the diaries, made a selection of her diary. They did not give information about the ratio of entries they selected. I felt they might have better included more entries and make the notes more concise. It was an interested read. It does show, as so many biographies before, that people wrestle for many years with problems in their lives and have a very hard time to change there basic habits.

Sunday, May 20, 2018

Three fold rotation symmetry

I thought about a way to visualize the long sequence of coloured rubber straps, and I came up with the following figure:

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In this figure there are ten triangles, one for each combination of the five coloured rubber strapts, such that the vertices are on a circle representing the repeated sequence. There are fifteen pairs of parallel lines, where each pair represent two combination occuring in both directions along the sequence. At first sight the figure seems to have some mirror symmetries, but actual it has a three fold rotation symmetry.

Monday, May 21, 2018

KunstenLandschap 2018

In the afternoon, I went to KunstenLandschap 2018 (Art and landscape), which is a route along 19 (or so) locations, where some art is on display. I followed the route from the first to the last location. Then I went back to one of the fighter bunker to watch a dance performance by Tess Lucassen and some others. There was also a puzzle quest. There were five locations where you could make yourself woodcut print in the form of a puzzle piece, that when put together formed one artwork of 40 by 60 cm designed by Elsbeth Cochius. I made a KML file for Google Earth of the route that I biked. I met several people that I knew. One of them was Kira Fröse, who had decorated the inside of a small shelter bunker (at location Number 11). I liked the following works the most:

Wednesday, May 23, 2018


At 09:58, I bought the book Oerol - logboek written (in Dutch) by Aleid Koskamp, Paul Edens, Jolly van Loon, and Linda Verkaai, published by Drukkerij Veltmann Enschede in 1996 from charity shop Het Goed for € 1.50. It is a collection of grey cardboard sheets held together by a spiral. Many of the pages contain printed photographs glued on the cardboard.

Gogbot Café

In the evening, I went to the Gogbot Café, which was held at Tetem art space, with the following talks: After a short break, Stelarc gave a Stick Man performance.

Monday, May 28, 2018

Three fold symmetry

There are another nine coloured strap sequences that have a three fold symmetry, but all these have at least six cases where a certain colour combinations of straps returns after a day. They are displayed below. I have aligned them such that the 'big' triangle is oriented in the same way, with one vertex on the right. I feel they look different from the sequence that I am using now.

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The sequences (from a total of 8,540 unique sequences with respect to permutations of the colours, starting position and direction) where found with the program rubberBands.cpp.


At two meter, the maximum temperature at weather station at Twente Airport was 29.4° Celsius and at 10 cm it was 32.1°. It would not surprise me if these are record high temperatures for this day of the year. In the past week the wind often comes from the East and becomes stronger in the second part of the day.

This months interesting links

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