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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.

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 wednesday day 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:
1 6 29 41 45 60 80 81 95 115 130 150 154 165 185 200 210 220 274 279

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.

Sunday, September 10, 2017

Gogbot: Day 4

I went with Andy to the former Coberco milk factory to see the Gogbot exhibitions there. The most interesting was a tapered kaleidoscope. I took several pictures inside it, one of which is shown here to the right. 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 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.

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 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.

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.

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.

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 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.

Monday, August 28, 2017

Kira Fröse

This afternoon, I bought a collage from Kira Fröse. I saw this work at the AKI finals 2017 exhibition. I met her for the first time during the opening of the exhibition AKI's serveertip, which ended yesterday.

Wednesday, August 23, 2017


At 17:29, I bought the book A Susan Sontag Reader written by Susan Sontag in English and published by Penguin Books in 1983, ISBN:9780140054347, from charity shop Het Goed for € 1.50.

Saturday, August 19, 2017

Solution for 7 and 8

I worked on the program for the the Irregular Chocolate Bar puzzle and found (maybe all) solutions for sizes 7 and 8. The program found 56 solutions for size 7. Here are twelve of these solutions:
1 6 11 15 21 25 29 31 35 39 45 49 54 59
2 3 9 13 19 23 27 33 37 41 47 51 57 58
3 11 13 18 23 27 28 32 33 37 42 47 49 57
5 6 11 15 21 25 29 31 35 39 45 49 54 55
6 7 9 17 19 27 29 31 33 41 43 51 53 54
7 8 17 18 19 28 29 31 32 41 42 43 52 53
8 11 13 18 23 27 28 32 33 37 42 47 49 52
9 12 17 19 22 23 27 33 37 38 41 43 48 51
11 15 16 21 24 25 26 34 35 36 39 44 45 49
12 13 19 22 23 27 29 31 33 37 38 41 47 48
13 21 22 23 27 28 29 31 32 33 37 38 39 47
16 17 19 21 26 27 29 31 33 34 39 41 43 44
For size 8, only three solutions were found, whiche are:
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


Tuesday, August 15, 2017

Brain machine

This evening at TkkrLab, I put together the brain machine that I bought at SHA2017. I sat at our work bench and followed the instructions on my tablet. I did not follow the instructions to the letter. For example, I did not extend the wire to the battery holder, but soldered the wire directly on the contacts of the battery holder. I used some double sided tape to attach the battery holder to the pair of glasses. I used one of the tie wraps to attach the PCB to the pair of glasses. I did not use any glue or scotch tape. I might if I apply the decoration. Several members helped me with drilling the holes and finding things I needed. I was happy I managed to finish it in one evening and several people tried it out.

Monday, August 14, 2017

Tetem and Bookshop Broekhuis

This morning, I visited TETEM art space, where I watched the videos By way of other directions by Lou Mouw and Ars Electronica Sparks Residency - Anouk Wipprecht on “Agent Unicorn” EEG wearable. At the start of the afternoon, I visited Bookshop Broekhuis. At 13:05:48, I bought the CD Passaggio: Ludovico Einaudi by Lavinia Meijer for € 9.99 and at 13:11:41, I bought a Moleskin Van Gogh Sketchbook for € 7.25 with 50% off.


With respect to the Irregular Chocolate Bar puzzle, I wrote down the following proof:
    Theorem: Let S be a set of natural numbers that sum up to n.m and that can be partitioned into n sets such that each set sums up to m, than for any pair i1 and i2 in S such that i1+i2=m, it holds that S-{i1, i2} can always be partitioned into n-1 sets that each sum up to m.

    Proof: Assume that S-{i1, i2} cannot be partitioned, while S can be partioned, than in all partitions of S i1 and i2 must be in different sets. There must be a partitioning P1, P2, .. ,Pn such that P1 contains i1 and P2 contains i2. Let {i1, i3, .. ,ik} (with k>3) the set P1, than i3, .. ,ik sum up to m-i1, which by assumption is equal to i2. It is now possible to construct a partitioning P'1, P'2, .. ,Pn where P'2 equal P2 with i2 replaced by i3, .. ,ik and P'1 equal to {i1, i2}. It is clear that P'2, .. ,Pn is a partitioning of S-{i1, i2} such that each set sums up to m.

After some puzzling, I discovered that there is no similar theorem for each combination of i1, i2, and i3 in S that sum up to m. This follows from a counter example, where S = {39, 40, 41, 98, 100, 102, 159, 160, 161} with n=3 and m=300. In this example, it does not work for 98, 100, and 102, because {39, 40, 41, 159, 160, 161} cannot be divided in two sets that sum up to 300.


Sunday, August 13, 2017

Who Stole My Spear?

This morning, I finished reading Who Stole my Spear by Tim Samuels, which I started reading on July 24, after I bought it on July 22. I found this a very interesting book. The book states that although in our modern society men are still in the majorithy in the higher regions of society, the bare facts are that in many areas men on average fare worse than women. The author argues that men have a harder time dealing with our modern society, which diverts furhter and further from our ancestoral hunting and gathering style of living. This books writes about important issues that should get more attention, especially among young men, because man usually do not talk about these issues.

Saturday, August 12, 2017


Friday, August 11, 2017


Tuesday, August 8, 2017


At the end of the afternoon, I returned from SHA2017 hacker camp, where I went to with some people from TkkrLab. This is the first time I went to such a camp and I had a great time. In the evening the camp was like an open-air disco with music and lightshows everywhere. One evening there was an event on the camp with home built vehicles, including riding pieces of furniture and also a KarTent on weels. I wrote two more badge apps: One for upcoming events (based on code from Event Schedule) and one named FFAA5E for setting random 'orange' pixels on the Pixelflut LED wall. Sunday morning, I bought the brain machine from Mitch Altman. I was a parking angle and did six shift with a total of about sixteen hours for which I was rewarded with meal vouchers and allowed me to enjoy the fantastic (mostly vegaterian) meals cooked for the volunteers. Notable talks I attended are:

Wednesday, August 2, 2017


September 2017
August 2017
July 2017
Juni 2017
May 2017
Alzheimer's Disease
Trip to China 2010
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