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Diary, September 2023

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Saturday, September 2, 2023


Last Monday, I found a piece of stone while during weeding at Hereenboeren Usseler Es. I used it to sharpen the hoe I was using. I thought about keeping it for that purpose, but I forgot about it. This morning, I found it at the place I left it. When I cleaned it with some water, I discovered that it was a piece of stonewhere. Below an image with pictures from three sides.

It looks like it is from the top of a round piece of earthware. I guess its diameter must have been about 7 cm. The top looks flat and the edge sticks a bit out. I have tried to determine it, but did not arrive at a final conclusion. My best guess is that it is from the period 1280 to 1400. But I could be totally wrong. I did find around 2008 some archaeological research was performed on the Usseler Es and that findings from various periods were found. At least from the Roman area but also possible settlements from the bronze or iron age. The reports (in Dutch) are:

I read that archaeological finds always have to be reported so I reported it, primarily because I want to know from which age it is. If I have to hand in the fragment, I am happy to do so.

Wednesday, September 6, 2023


I got a response from an archaeologist with respect to the piece of stoneware that I found last Saturday. The piece probably comes from the foot of the pottery. The rim on the top half of the middle photograph is most likely a fracture surface that the bottom was attached to. So, the pieces are shown upside-down on the photographs. It is difficult to estimate the age of the piece, the best guess is that it is probably from the Middle Ages (500 - 1500), although it cannot completely ruled out that it is even older and comes from Roman times. The find is interesting but not really of much archaeological significance because it was made in the top soil layer that has probably been plowed many times and disturbed in other ways. There is a long tradition that arable areas were raised with manure and peat soil from elsewhere.

Thursday, September 7, 2023

Chestnut and hazelnuts

Conny gave me a chestnut and two hazelnuts, which she found yesterday. The chestnut was still half in it shield. We decided to plant the nuts in the back garden. I placed them, half in the soil between some sunflowers. Almost all of the sunflowers have topped over. We have had and still have a lot of flowers in the back garden. Still can smell the scent of them. We harvested two uniform-colored zucchini from our garden from three plants. The plants got a lot of male flowers. We do not know why they did not bear more fruits (growing from female flowers). The two grapevines that we planted on May 2 have not grown much, maybe because they were in the shadow of some flowers. The wisteria sinensis 'Prolific' is doing fine. The clematis have been doing less well. One of them seems to have died.

30.0° Celsius

The temperature at Twenthe Airport has gone up to 30.0° Celsius, which breaks the previous record of 26.7° on this date in 2005. Yesterday, the temperature reached 30.2° Celsius and the days before 29.7° and 25.6° Celsius. Which means that if tomorrow the temperature reaches 30.° again, which is quite likely, it means we have a regional heat wave.


This evening, I went to GOGBOT with the title Feed your head: Drugs & AI. The exhibition only opened around nine in the evening after the official opening speeches. This is the twentieth time that GOGBOT has been organized and the last time that Kees de Groot will organize it. I found the following works of the exhibition noteworth:

At 22:48, I bought the book How to Change Your Mind written by Michael Pollan in English and published by Penguin Publishing Group in 2019, ISBN:9780735224155, from Underbelly for € 16.00.

Friday, September 8, 2023

GOGBOT and more

I first went to TETEM art space to see the the exhibition Liquid Dreams by Annika Kappner. This is also part of GOGBOT. During the guided meditation of the exhibition, I fell asleep. Next, I went to the other GOGBOT locations. I found some more works notable:

I bought three cotton shirts for € 29.99 each. I next went to bookshop Broekhuis where at 16:16:03, I bought the book The Andy Warhol Diaries written by Andy Warhol (in English), edited by Pat Hackett, published by Hachette UK in 2009, ISBN:9780446571241, for € 20.00.

29.8° Celsius

The temperature at Twenthe Airport has gone up to 29.8° Celsius, which breaks the previous record of 27.8° on this date in 2005.

Sunday, September 10, 2023

Who owns the land? the countryside?

I went to the exhibition Van wie is het (platte)land (which you could translate to 'Who owns the land? the countryside?') at Rijksmuseum Twenthe. It is actually a combination of three exhibitions of which one is also part of the photo manifestation that will be held in Enschede this fall. The first visited the exhibition Terra Libera (Latin for 'The Free land'). I found the following works noteworth:

Works from the second exhibition, called Extractivism, I found noteworthy are:

From the normal collection, I saw:

Finally, I saw third exhibition, which is part of the photo manifistation, consiting of:

In the garden, Strings of Soul was playing.

Regional heat wave

I was looking for what was the last record temperature for yesterday, so I downloaded a zip file with weather data for weather station 290: Twente starting from 1951 till yesterday. I was a bit surprised that it mentioned higher maximum temperatures than the ones I find on weather graphs on a Dutch rain radar website. This might be because these graphs are based on a less frequent sampling, thus missing some of the fluctuations. Starting from September, it mentions the temperatures: 25.6°C, 29.7°C, 30.5°C, 30.2°C, 30.0°C, and 28.8°C (for yesterday). That means we had already had a regional heat wave on Friday according to the definition used by the Royal Netherlands Meteorological Institute. Today, the temperature at Twenthe Airport reached (at least) 29.2° Celsius, which breaks the record of 28.7° Celsius in 1959.

I wrote a program to process the file and list the records. Below the list starting from 2020. If a higher (or lower) temperature was achieved than I mentioned, than I have added the mentioned temperature. There are also some that I did not mention. Of course, this might be because I missed them, but it is also possible that it is not real a record, because a the temperature was already reached in a year before 1951.

Tuesday, September 12, 2023

OSV2020 software hacked?

This evening, there was a news item on Dutch national tv (broadcast at 18:00) about the Dutch vote counting software OSV2020. See also: Hacker discovered serious vulnerabilities in Dutch vote counting software. It was not in the actual counting software, but the investigators found some passwords through the installer, allowing them theoretically, to replace the official counting software with a replacement that could change the summation. For a detailed description, read: The importance of post-build audits: Do you know what you ship? It was verified that no actual attack was performed and the the vulnerabilities were closed. The official report in Dutch about this is: Opgeloste beveiligingsmelding inzake de ondersteunende software verkiezingen (OSV2020). This again emphasizes the need for totally independent verification based on the published files.

Wednesday, September 13, 2023

After the Storm

This evening, I visited the exhibition After the Storm by Fernanda Gomes (on instagram). She arrived on July 5 in the Netherlands by plane and was stuck at the airport due to the trains not running because of the Storm Poly. In the projects that she made since her stays, she was wearing a blue dress. At the exhibition she wore a green dress. I understand that that is related to the next theme. Before she did a project with the colour red. I did not stay until the preformance that she was going to give.

Thursday, September 14, 2023


I went to Amsterdam. On the way there, I traveled through Utrecht where I left the train station to visit bookshops Steven Sterk and Aleph (just shortly). In Amsterdam, I went to see the exhibition The Art Experience at RTXP. It mainly consisted of reproduction of famous paintings. They did not mention the names of the artists that made the reproductions. There were some original art works. I found the following noteworthy:

Next, I visited Foam Fotografiemuseum Amsterdam where I saw a number of exhibitions. I first watched the documentary Seahorse Parents by Miriam Guttmann. Next, I saw the exhibition Next Level: Sara Cwynar in reverse order. I found the following works noteworthy:

Then I saw the major exhibition: A Play of Light and Shadow with photographs by Ara Güler. The photographs do not have titles. They are shown with a location and a date. I found the following photographs noteworthy:

After this visited, I visited the following bookshops: De Slegte, Athenaeum boekhandel Amsterdam, The American Book Center, and Scheltema Boekverkopers. The later used to have a second hand section on the top floor. The remaindered books (ramsj in Dutch) that used to be on the second or third floor now can be found on the top floor. I found it a bit chaotic. I also went to the high-end department store De Bijenkorf, where at 18:06:24 I bought a Moleskin daily planner for 2024 for € 23.90. The trip home by train took a bit longer due an international train requiring reservations and two trains that were canceled. I finished reading the book De Broodschrijver: over de Herman Brood-biografie van Bart Chabot by Arjan Peters, which I started reading this morning after I bought it on May 30. (Later, I discovered this was actual the second reading of the book, the first time being April 3-4, 2011.) The book contains interviews of Bart Chabot about his writting the biography of Herman Brood. I read one part of the four book biography. Chabot wrote this during a period of seven years. It was interesting to read (for a second time).

Monday, September 18, 2023


Last weekend, I worked on my Exact Cover program in order to see if I could get a beter estimate for the Octopuszle. I did get it to work and also fixed a problem with calculating the estimate based on statistics. I did find many new solutions to the puzzle, but the estimation did not converge. This evening, I let it run with slightly different parameters and it came back with much lower numbers. The numbers I have been seeing are in the 10163 and 10166 range. Which is similar to what I reported before. Among the solutions that were found by the various runs, there were solutions that where rather similar, sometimes just with four tiles being swapped. When I thought about this, I realized that it is actually quite likely that these kind of swaps occur in any given solution (due to the birthday paradox).

Late Roman time

I got a reply to the report that I submitted on the second of this month about the piece of stoneware that I found. It has been registered under number 5463631100. The report states that it is (in Dutch) 'ruwwandig aardewerk, gedraaid', which translate to: 'rough-walled earthenware, turned'. The report also states that it is possibly from the late Roman time, which (in the Netherlands) is the periode from 270 to 450. This is a bit earlier than the one I got on sixth of the month. When I replied to that one that the piece was quite hard, I got the answer that it is more likely that it is from a later period.

Sunday, September 24, 2023

Exhibition of 6Sprong artist

In the afternoon, I went into the city and visted the exhibition Ateliers 6Sprong op bezoek at Concordia with works by artist who have a studio at 6Sprong. I liked the following works:

Monday, September 25, 2023


This weekend and this evening, I spend some time writing a program to analyze the solutions to the OctoPuszle I found last weekend. First, I wrote some code to check the number of pairs of tiles that can be swapped, meaning that there exists a pair of horizontal, vertical or diagonal touching tiles that can be swapped with a similar pair elsewhere because they match on the outside, but differ on the inside. I checked this for all the solutions found. Below the number of solutions with the given possible swaps:
 0  287
 1  488
 2  353
 3  133
 4   61
 5    9
 6    4
From this the average number of pairs of tiles that can be swap is 1.427715. Next, I wrote some code to compare each combination of two solutions to see how many differences there are between them and the smallest rectangle area in which the differences occured. The most common number of differences between two pairs is 253, meaning that there are just three tiles the same. This is probably close to average number of tiles that any two solutions have in common. Of the 890445 combinations of two solutions there were 184825 that had 253 differences. Although there are zero combinations with 238 differences, there are many combinations with 54 and less differences. There are 1256 combinations with 35 differences. The frequences of the difference do not match with the actual differences for all solutions. This is due to limited number of solutions, some rather close to eachother, that were found with the algoritm that was used. It is interesting to investigate the average number of solutions that have a certain number of differences.

Saturday, September 30, 2023

Wheat grain cleaning

Today at the issue of Herenboeren Usseler Es we received approximately two kilos of wheat grain to clean. The wheat had already gone through a winnowing machine twice. This is a hand-driven machine with which the wheat is sieved and the chaff is blown away by wind. There is also a lot of grass seed among the wheat. The purpose of cleansing (also called reading) is to remove the last impurities. This mainly concerns seeds that are still among the wheat. We quite enjoyed doing it. I did it at the end with a plastic fork on a large plate, filling the plate with a handful of grain each time and then push the grain forward with the fork and remove all the rubbish from between. The last bit from the bag was the most work because most of the rubbish had slowly fallen to the bottom by the shaking of us getting hands of grains out of the bag. Last week, approximately 40 kilos of wheat was already ground at the windmill in Lonneker.

This months interesting links

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