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Diary, September 2017

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Friday, September 1, 2017


I went to Amsterdam and visited some bookshops. First I went to Bookshop Scheltema. I saw some interesting books, but I did not buy any reasoning that I could better buy them tomorrow on my way home. Next I visited Athenaeum, where I looked a round a little. From there crossed the road the American Book Center. At 14:14, I bought the book The Truth by Neil Strauss. Last I visited Het Martyrium. I considered buying the complete works of James Joyce and Being and Nothingness by Sartre.

In the evening, I went to the opening of the exhibition Het Idioom van de Abstractie at Art Chapel, where there are some works by Peter Struycken. I met with some people I knew and got some questions of the SHA2017 badge I was wearing.

Saturday, September 2, 2017

On Photograph

In the morning, I finished reading the book On Photography by Susan Sontag, which I started reading on June 12. I bought it on Saturday, April 2, 2016. The book presented some interesting insights, but I also found it rather philosophical and hard to grasp. What often is lacking, for me, is a clear structure of the argument she is trying to make. It looks like she starts with an idea and then wanders around all kinds of corners and end somewhere close to where she started. I got the impression that much of what she wrote did not stick with me. Maybe I am not smart enough to comprehend her line of thinking.


In the afternoon, Meindert and I visited some galeries. First we brough a short visit to Torch Gallery and watched the Grayscale exhibition with works by Alain Laboile, Louise te Poele, and Hengki Koentjoro. Next we went to Ron Mandos to visit the Best of Graduates 2017. I voted for Maarten Broekhuizen with his work The Post Topographic. I also liked (parts of) the work Best of Breed by Valentina Gal. After we brought a short visit to Gallery Borzo, we went to Huis Marseille: Museum voor Fotografie. There we saw some recent works by Juul Kraijer.

Thursday, September 7, 2017

Gogbot: Day 1

Around four in the afternoon, I arrived at in the city center to help 'decorate' the TkkrLab stand on Gogbot. We were located between the info desk and the bar. I watched part of a performance by Empress Stah (with a laser) in the middle of the Step in the light installation by Michel Suk. When I left, I took some pictures of Museum of the moon by Luke Jerram. One of them.

Friday, September 8, 2017

Gogbot: Day 2

It was a rainly day. For most of the afternoon and the evening, I stayed at TkkrLab stand at Gogbot. During the relatieve quiet afternoon, I build a Creep Cluster by Reverselandfil (following the build guide) and in the evening, I joined them with their noise performance on the stage on the square for a quarter of an hour. I looked around in the Grote Kerk and saw: A thing and its essence by Joseph Klibansky, Phyllotaxis by Daan Johan and Joris Strijbos, and works by Freek Wieringa. At Concordia, I saw Cogito by Daniela de Paulis and Fractal Shorts by Julius Horsthuis. At Menistenkerk, I had my brain 'scanned' with The Brainlight by Laura Jade. I also saw Superpower Studio by Dominica Chen (which I already at seen at the Rietveld Academie on July 9, 2017 ) and I looked at a Beowulf cluster of 37 Rasperry Pi's. At the end of the evening, there was another performance by Empress Stah, this time before the church in a transparend sphere.

Saturday, September 9, 2017

Gogbot: Day 3

Together with Andy, I visited TETEM art space, where we walked around and saw Spectra by Matthijs Munnik. The effect of seeing all kinds of colours in a blinking light is familiar to me. Still interesting to see it.

Sunday, September 10, 2017

Gogbot: Day 4

I went with Andy to the former Coberco milk factory to see the Gogbot exhibition there. The most interesting was a tapered kaleidoscope. I took several pictures inside it, one of which is shown here above. The other exhibits that I found worth mentioning are:

The Truth

Finished reading the book The Truth: An Uncomfortable Book About Relationships by Neils Strauss, which I started reading on September 2, the day after I bought it. This book continues where his book The Game, which I read in July, ended and is even more interesting and thought provoking than that book. I very much enjoyed reading this book and it realy made me think about my own life.

Saturday, September 16, 2017


I went to the opening of the exhibition Wegzeichen with works by Carina Schüring organized by Kunstverein Vreden. Bernd Sikora gave an introduction. Although it was in German, I had no problem with understanding it. Although I had seen the work recreating familiarity last year, I appreciated it much more than I can remember, probably because of how it is exhibited. I also like her work embracing insecurity. It was also nice to see the drawing Alles (Everything) again. I also bought Carina Schüring Portfolio 2017 with a introduction by Arjan van Helmond from her for € 35.00. (One of three copies as I found out after I bought it.)

Heliophile & Voltmeister Modular

In the evening, I went to a live performance of Heliophile for their debut CD Permeate. Before their performance, there was a performance of Voltmeister Modular. I bought the CD and listened to it at home.

Friday, September 22, 2017

Solutions for 9

In the past month I have been thinking about an alternative algorithm to tackle the Irregular Chocolate Bar problem, but it has failed to materialize. This week, I decided to see if I could improve on the existing algorithm to get at least some solutions. It is always nice if you can limited you search space by an upper limit. I started the program yesterday afternoon and by the end of this evening, it already found over fifty thousand solutions with 20 integers. This makes me wonder if there is a solution with 19 integers. These solutions are found by constructing a 'chains' solution for 18 integers and then twice split an integer into two. The improvement on the algorithm is that it first performs some check on the solutions for 18 integers with an alternative knapsack algoritm to see if it possibly could contain a solution with some additional splitting, before trying all possible splits and testing them against the existing algoritm. The first solution found by the program is:
9 set:  1 6 29 41 45 60 80 81 95 115 130 150 154 165 185 200 210 220 274 279
5 buckets with 504:  95+130+279 80+150+274 29+45+210+220 1+6+41+60+81+115+200 154+165+185
6 buckets with 420:  60+81+279 6+45+95+274 200+220 80+130+210 29+41+165+185 1+115+150+154
7 buckets with 360:  81+279 6+80+274 45+95+220 150+210 1+29+130+200 60+115+185 41+154+165
8 buckets with 315:  1+6+29+279 41+274 95+220 45+60+210 115+200 130+185 150+165 80+81+154
9 buckets with 280:  1+279 6+274 60+220 29+41+210 80+200 95+185 115+165 45+81+154 130+150

Tuesday, September 26, 2017


It is clear that the fall has started. I saw some very large mushrooms along the road. At 10:21, I picked up six big chestnuts from a tree on the Hengelosestraat near number 569. There were many more on the ground.

Brain machine

A friend of mine wanted to have a brain machine like the one offered by Ada Fruit, but when it turned out that the international shipping costs were rather high, I decided to build one myself from parts. I started with the design by Chris Sparnicht and took some ideas from the brain machine from Ada Fruit with respect to the schematics of the headphone. I also decided to use a single potmeter to control the volume by putting it between the 'ground' of the earphones and the ground. I am aware that this could cause some crosstalk when the volume is reduced, but I hope it is not going to be a big problem. While at TkkrLab, I arrived at the principal schema as displayed on the right and made a shopping list of parts. I bought a cheap Arduino Nano clone from the stock at TkkrLab.

Thursday, September 28, 2017

105869 solutions

The program for the Irregular Chocolate Bar problem for up to and including 9 equal divisions has found 105869 solutions with 20 integers starting with three 'chains' and two additional cuts. A 'chain' is a sequence of integers, where each pair of consecutive interers add up to alternating 280 and 315. It is now working on starting with a 'necklage' and three additional cuts, but has not found any solutions yet. It would not surprise me, if it does not find any aditional solutions. I checked if any of the solutions could be divided into 10 equal divisions, but this was not the case. Below the 'smallest' solution is given, with respect to the integers being used.
9 set:  31 60 80 85 95 99 109 111 115 120 121 124 150 156 159 160 165 185 195 200
5 buckets with 504:  109+195+200 159+160+185 95+120+124+165 31+85+111+121+156 60+80+99+115+150
6 buckets with 420:  99+121+200 60+165+195 115+120+185 80+85+95+160 111+150+159 31+109+124+156
7 buckets with 360:  160+200 165+195 60+115+185 80+121+159 95+109+156 99+111+150 31+85+120+124
8 buckets with 315:  115+200 120+195 31+99+185 150+165 60+95+160 156+159 80+111+124 85+109+121
9 buckets with 280:  80+200 85+195 95+185 115+165 120+160 121+159 124+156 31+99+150 60+109+111

Friday, September 29, 2017

885 solutions for 10 with 22 integers

While one program is still working on finding solutions for the the Irregular Chocolate Bar problem for up to and including 9 equal divisions, I decided to also start a run for up to and including 10. To my surprise it found 885 solutions with 22 integers. It is possible that there are solutions with 21 integers. The 'smallest' of the 885 solutions, with respect to the integers used, is:
17 45 52 53 80 81 95 96 105 108 109 111 115 116 136 137 143 144 171 172

Saturday, September 30, 2017

Brain machine

Last week, I bought the following parts from STORES for the brain machine: This afternoon, I spend about four hours working at TkkrLab at assembling the brain machine. I spend some time removing some material from the PCB of the Arduino Nano near the USB connector with a file, to make it fit in the box. Next I spend some time putting the components on the PCB. I also attached some wires (not all) that will connect to the jacks, the potmeter and the reset button on the top part of the box. Below a picture of the PCB in the box, where I added some red lines to indicate how the components are connected on the back, and a picture of the back of the PCB.

This months interesting links

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