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Diary, November 2021

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Monday, November 1, 2021

60 years

I was born on Wednesday, November 1, 1961 at 9:45 in the morning. That means that today, I will be 60 years according to the calendar and 21915 days old. But how old am I really? The tropical year, the time that it takes for the seasons to return, is said to be 365 days, 5 hours, 48 minutes, and 45.19 seconds. Yesterday, around 22:30 in the evening, it was 60 tropical years since I was born. But the tropical year is shorter than the sidereal year, the time taken by the Earth to orbit the Sun once with respect to the fixed stars, namely 365 days, 6 hours, 9 minutes, and 9.76 seconds. That means that, today at 18:54 it will be 60 sidereal years after I was born. The average anomalistic year, the time taken for the Earth to complete one revolution with respect to its apsides, is 365 days, 6 hours, 13 minutes, and 52.6 seconds. That means that, today around 23:37 it will be 60 average anomalistic years since I was born.

My colleagues gave me some presents. I got the book Journal 29 Revelation: Interactive Book Game written by Dimitris Chassapakis in English and published by Rain Projects Software Developers Limited in 2018, ISBN:9780692183052 and a bag of Gyokuro tea.

At 17:50, I bought the book Kröller-Müller: honderd jaar bouwen en verzamelen written by Rudolf Willem Daan Oxenaar in Dutch and published by Joh. Enschedé in 1988, ISBN:9789070024543, from charity shop Het Goed for € 2.25.

In the evening, Conny and I went to see and experience Foundscape Orchestra by Daniel Maalman at the former printing press hall of De Twentsche Courant Tubantia newspaper in Enschede. The two fuzzy silhouettes seen in this video are the two of us.

Friday, November 12, 2021

Palindrome date (DD-MM-YY and YY.MM.DD)

Today is a palindrome date when written according to the DD-MM-YY format: 12-11-21 and the YY.MM.DD formats: 21.11.12. The previous such date was November 2, 2020 and the next will be November 22, 2022. It is also a double date when written according the DD-MM-YY format.


At 10:05, I bought the book Ulysses written by James Joyce in English and published by Wordsworth Classics in 2010, ISBN:9781840226355, from charity shop Het Goed for € 2.15.

Saturday, November 13, 2021

Wasserprobe | Waterproef

I biked to Tetem, where I saw the exhibition SprintExpo 'If it fools you, it is not fake' with works by Valentina Gal, Diana Gheorghiu, and Sonia Mangiapane. This is part of the Fotomanifestatie Enschede '21 for which I already visited the other locations two weeks ago on October 30. Next, I went to XPO to see the exhibition Wasserprobe | Waterproef with works by Judith Schepers and Regine Wolff. The floor of the exhibition was filled a layer of water. There were some rubber boots available, but I decided to take of my socks and shoes to wade through the water. I talked a little with Judith Schepers and at 15:40, I bought the catalogue of the exhibition for € 24.00.

Sunday, November 14, 2021


In October 2012, I bought a FAKTUM kitchen from IKEA, which was installed by my brother and one of my sisters. It came with a 25 year warranty. However, in 2014, IKEA introduced the METOD kitchen system, which is incompatible with FAKTUM. In the first years after the introduction of METOD, FAKTUM reserve part remained available. But that is no longer the case. There are some companies that have started producing spare parts however. Because the fridge of Conny was a bit larger and a lot newer, we decided to remove the build-in fridge from the FAKTUM kitchen and use the space for storage. This required to install some new shelves and fix the hinges. I tried to order the right type of shelves from one of these spare parts websites. It was kind of hard to find the right type of shelves due to the broken interface of the website. They offered a set of two shelves for 45 €. I wanted to order two of these sets only to discover that the transportation costs where another 125 €. I decided to have a look hardware store and for about 30 € we got all the materials to create four shelves and fix the back of the cupboard. The doors of the cupboard used to be attached to the door of the fridge, but now that the fridge was gone, the doors would no longer close. To fix this the hinges needed to be replace by soft closing hinges. I tried searching the internet for the original soft closing hinges for the FAKTUM kitchen, but failed to find any. Instead we bought two sets of two KOMPLEMENT soft closing hinges (intended for the METOD kitchen system) and I spend some hours trying to fix them by drilling some new holes in the sides of the cupboard and makes some holes in the doors a little larger. Today, I succeeded in fixing the doors and get everything to work as we wanted. If I ever will get a new kitchen, I wonder whether it will be an IKEA kitchen again, as it seems that the 25 year warranty has little meaning if something breaks down or if you want to modify your kitchen.

Friday, November 19, 2021

Formnext 2021

Yesterday afternoon and today, I visited the Formnext, the leading trade fair for additive manufacturing and the next generation of intelligent manufacturing solutions, which is held on the Messe Frankfurt. I looked around halls 12.1 and 11.

Monday, November 22, 2021

struct or class

I have been using the programming language C# for two years, after having worked with C++ for many more years. Recently, I was tricked again with some quirck of C#, which is related to a fundamental difference between struct and class. In C++, struct and class are semantically equivalent in their behaviour, except with respect to a small detail, which partly might explain why I was being tricked again. Take for example, we want to sum value based on some key and also count the number of values, which for example could be used to calculate the average afterwards. (I am aware that this probably could also be done with some clever LINQ expression.) For this we define a type Values with a Sum and Nr member and implement the following method:
  public void AddValue(Dictionary<int, Values> dict, int key, int value)
    if (dict.TryGet(key, out Values values))
      values.Sum += value;
      dict.Add(key, new Values() { Sum = value, Nr = 1 };
The idea of this method is to check if the key is present with the TryGet method and then either modify the value or add a new entry in the dictionary. However, this code does not work when Values is defined as a struct instead of a value, because when it is defined as a struct the method TryGet returns a copy of the value in the dictionary and modifying that value does not change the value in the dictionary, where as when Values is defined as a class it returns a reference to the value in the dictionary. C# is one of the programming languages that have decided to hide the difference between a value and a reference to a value. In languages, like C this difference is made more explicit, which requires more syntatical sugar. This a common problem when deciding to make things explicit or implicit.

Friday, November 26, 2021


The new B.1.1.529 variant is going to be the test if we learned anything about dealing with COVID-19. Besides Botswana and South Africa, it already has been detected in Hong Kong and Israel. Some countries are closing their borders, but I wonder whether we will be able to confine it. There are indications that it more infectious than the now dominant Delta variant and due to the high number of mutations in the spike protein, there is a reasonable chance that current vaccins will be less effective against this variant. Actually, it shows that we have failed to deal with COVID-19, because scientists have warned for the chance of variants that evade current vaccins and that it was just a matter of waiting before it would appear.

Saturday, November 27, 2021


At 10:01, I bought the book Het gezicht van de AKI edited by Maarten Binnendijk, Saskia Huisman, and Regina Kroeders, written in Dutch and published by Hardyuitgeverij in 1997, ISBN:9789075522075, from charity shop Het Goed for € 1.60. Yesterday, I already saw this book, but did not buy it because I was afraid that I already had a copy of it. I went back this morning, after I concluded that I did not have it yet.

61 of 624

Yesterday, two planes from South-Africa arrived in the Netherlands with 600 passangers in total. Before they boarded the plane all of them had to show a negative test result (with a rapid nasal test, for example) not older than 24 hours. On arrival, 61 of them tested positive with COVID-19. Those who tested negative were free to leave but where requested to stay in isolation for five days. Those who tested positive and had a place where they could stay isolated either by themselves or with the group they traveled with, where also allowed to leave. They were requested to stay in isolation for five days if they showed no symptoms and for seven days if they did show symptoms. People who arrived from South-Africa in the past days are urged to have themselves tested. Today, the samples from those who tested positive will be checked for the Omicron variant. There is a big chance that someone in the Omicron variant is already spreading in the Netherlands and I suspect that it will not take long before it is spreading uncontolled as well.

Overkill Festival

I went to the Overkill Festival. I wore the necklace Conny made from the contents of the .Festival Box we got Last year. I looked around. I liked the following art works: The theme of this tenth Overkill Festival is Collective Masquerade. Because of this there were several 'makeup' stations around the venue. At one of them, I put a dot of nail polish on the nail of my left thumb and than pushed the nails of my thumbs together, which transfered part of the nail polish to the nail of my right thumb. (Before I left the venue, I removed most of the polish as not to scare other people.) I sat around and talked with some of the people of the modular meet-up. I left before the modular synthersizer music event started in the evening.

Walking around the city

After having visited the festival, I walked through the city. At Fotogalerie Objektief, I watched the exhibition Klei with pictures by Ben Vulkers. I walked into the Beeld & Aambeeld gallery, where there were two works by Billy Foley on display. At the coffee and thea shop Simon Lévelt, I bought a tea water thermometer. Finally, I visited bookshop Broekhuis, where at 16:49:16, I bought the book Nietzsche written by Paul van Tongeren in Dutch and published by Amsterdam University Press in 2016, ISBN:9789048529414, for € 5.95.

Monday, November 29, 2021

A little bit of snow

This morning, when I went outside, I noticed a little snow on some parts of the grass in the garden.

13 cases of Omicron variant

It was reported that the Omicron variant was found in 13 positive tests so far. These are of the 61 that tested positive last Friday from the 624 passengers that arrived in two planes from the Netherlands. A similar amount of passangers arrived in the past days, but they were not tested like those on the Friday, maybe because the way that was done was critized. In the past days those who continued elsewhere were not tested and those who left the airport were offered a free test. About half of the people did not take the test. There is currently no law that allows the government to force people to take a test. So, the operation of last Friday, which drew some critizism with respect how it was executed, seems to have been an exceptional event. But it does give some interesting information. From this one could make some estimates how many people could already have been infected with the Omicron variant in the Netherlands.

Tuesday, November 30, 2021

Omicron variant spreading

Today, it was reported that the Omicron variant of COVID-19 was detected in test samples taken on November 19 and 23. The cases are not related. One of the two persons has been in one of the countries in the south of Africa. The other has not and a connection with someone coming from there has not been established yet. This suggest that the variant has already been spreading over the world undetected and probably cannot be confined anymore.

This months interesting links

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