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Diary, May 2022

Sun Mon Tue Wed Thu Fri Sat
  1   2   3   4   5   6   7
  8   9  10  11  12  13  14
 15  16  17  18  19  20  21
 22  23  24  25  26  27  28
 29  30  31

Sunday, May 1, 2022

Irregular grids

In the past weeks, I wrestled a lot with finding a correct algorithm for the generation of irregular grids of squares and equilateral triangles. For a long time, I worked on an algorith that would generate all possible strings of 'pieces' (the triangles and squares at the various orientations) from a give string of pieces. But it was only after I decided to look at the five possible slopes of the lines on the top and bottom of the strings of pieces and generate all possible strings of slopes from a given string of slopes, that I succeeded in implementing the working program irst.cpp this evening. It also groups all strings of slopes into groups that can reach each other the program finds a total of 455 groups. Many of these groups have just one or a few elements. There are also groups that have strings of slopes that have not been investigated (marked with the text 'FAIL'). This is because the strings of slopes are generated by searching all strings of pieces up to and include a length of twelve that return to the first element of the string.

Wednesday, May 4, 2022

Uploading bitstream to FPGA

Yesterday evening at TkkrLab, I talked about helping out with developing the firmware for the MCH2022 Badge. I am going to look into uploading bitstreams to the FPGA through the USB connector. The first idea is to add a menu option to the main menu which listens to the USB connector for a bitstream to be uploaded to the badge and which when the bitstream is received, uploads it to the FPGA. There is already code available to upload a bitstream from an SD-card. I will also have to develop a program for sending a bitstream from a file to the USB. I had a look at the code of iceprog, the program to upload bitstreams to, for example, the UPDuino. This program talks to a flash-chip. So, it is not really applicable. This evening, I spend cloned the firmware repo and build it, running the Install Prerequisites for ESP-IDF and next using the following commands:
git clone
cd mch2022-firmware-esp32/
git submodule init
git submodule update
. esp-idf/

I only found the BADGE.TEAM > ESP32: firmware development > Getting started page after I did this. I do not know whether this is still up-to-date. I spend some time studying the code in the 'main' folder and from there also some files in some other folders.

Thursday, May 5, 2022

De vijfde lijn

I finished reading the book De vijfde lijn (Dutch for The fifth line) which is based on a number of talks between Steven Aalders (a Dutch abstract artist) and Robert van Altena (a Dutch art critic). I started reading the book on February 23. I bought it on January 26. Just like with Peter Struycken, colour plays a central role in his works. He makes use of simple shapes, mostly rectangles. Compared to Struycken, it seems to me that his approach towards colours is more intuitive (based on emotions) whereas that of Struycken seems to be more rational. On page 36 of the book Struycken is mentioned along with Jerry Zeniuk (a German artist) and Daniel Buren. On page 237 Aalders makes a remark how Rembrandt in his painting Self-Portrait with Two Circles made use of the four colours from the Greek antiques: Whites, blacks, ochres and reds. Struycken has studied the use of these four colours from the Greek antiques through history. On page 192 the book references Sentences on Conceptual Art by Sol LeWitt.

Sunday, May 8, 2022

Spruce Street, Berkeley

I have started reading the book A Heartbreaking Work of Staggering Genius. I was reading Chapter 2, where it mentioned Grotto Rock. After some map searching, it seems that they lived at 876 Spruce Street, Berkeley. The book also mentions the author walking down Marin Street, but that must be Marin Ave. Although Cragmont Elementary School is just across the street, in the book it says that they send Toph to Black Pine Circle. On page 59, there is a mentioning of a nude beach. This could either be Gray Whale Cove State Beach or a smaller one closer to Montara that is now closed.

Addition: On Monday, I discovered that Cragmont Elementary School was closed between 1990 and 1999.

Saturday, May 14, 2022


Today, Conny and I arrived in the village Pannerden where we are actually staying outside the village near the ferry crossing the Pannerdens Kanaal to Doornenburg. The ferry is one of eleven motor supported reaction ferries in the Netherlands. There are three small boats up stream through which the ferry is connected with a cable to the anker point in the middle of the canal. After we arrived, we sat outside and watched the sunset. We will stay here for about a week and make trips to surrounding areas and cities.

Sunday, May 15, 2022

Tolkamer and Hochelten

In the morning, Conny and I, went to the village Tolkamer. The name is Dutch for toll room. It is on the riverbank of The Rhine with Germany on the other bank. For about 7.8Km the border the Netherlands and Germany is in the middle of the Rhein. Actually, the west half is the Bijlandskanaal. In the afternoon, we visited the village Hochelten, which is part of Elten. It is just across the border in Germany. Through the ages it has either belonged to the Netherlands and Geramny. The last period it belonged to the Netherlands was between April 23, 1949 and August 1, 1963. Even now it is surrounded by the Netherlands from three sides. There is a mixed population of Dutch and Germans living in the village. We met with at least one German person there who spoke perfect Dutch. Hochelten is on a hill that is about 82m above sea level. On the top of the hill, there is the church St, Vitus. The first church was build in 967 on this spot. We visited the church. Before we came to the church, we saw Der Stein Tor (German for The Stone Door) sculpture by Christoph Wilmsen-Wiegemann. Near the church there was also a stone chair from which you could see some dent in far away hills that could be seen between the 'door'. We wondered if on that far away hills there would be a similar sculture. In the evening, we discovered that dent is near the Klever Schlosspark. The church belonged to a Damenstift, which was also on top of the hill. We also visited the Brususbron, a 57 deep well on the top of the hill, which was probable dug to provide water for the damenstift. The name refers to Nero Claudius Drusus, who although he did campaigns in the area, is not believed to have visited the hill nor commanded to dug the well.

We also visited a number of border poles in the morning and afternoon. These are:

Monday, May 16, 2022

Lunar eclipse

Conny and I woke up around a quarter to four and went outside to see the lunar eclipse. The weather prediction stated that it would be cloudy, but the sky looked clear. However, when the eclipse increased and the moon went down, it became clear there were clouds at the horizon. Due to the sun getting up at our location, the sky became too light to see the part part of the moon and see the redening that is typical for a blood moon. Below a crop of one of the last good pictures Conny took from the moon. After this, we turned around our chairs to watch the sun rise. Below one of the pictures Conny took from the red sky before the sunrise. We also watched the first trips of the ferry going from the otherside to our side and back. We were surprised by the number of cars on those trips guessing that there must be a number or regulars taking these first two trips.

Emmerich, Schenkenschanz, and Kleve

This afternoon, Conny and I made a trip through Germany. We first visted Emmerich am Rhein where we walked along the Rhein front and visited two Roman Catholic churces. Next we travel to the Spyk hamlet on the south front of the Rhine were at 13:35 we found the border poles 660 (D). One of them was a little closer to the river in an area that we could not visit. We saw some dark clouds and heard some thunder. We continued to the remote village Schenkenschanz and waited some time in the car for the rain to stop before we walked through the village. At the location of the village there used to be a fortress at the location where the Rhein would split into the Waal and the Nederrijn. Through several efforts to canal the river, that location has now changed close to Pannerden. The last place we visited was Kleve were we only visited the Klever Schlosspark. Just across the road there is a long pond going into the direction of the church at Hochelten. This only becomes visible from the lookout point higher up the hill. Around the pond there is a pathway named after the German artist Joseph Beuys.

Tuesday, May 17, 2022


This afternoon, Conny and I went to city of Nijmegen. We first visited the Valkhof Museum where we spend most of out time at the Moving Stories, the riches of the Limes exhibition. It is a mixture of archaeological artifacts and modern art. I liked the following items from the exhibition: From another exhibition about Nijmegen, I would like to mention the following works: From the exhibition Space: Moonshot part two, I would like to mention the following works: (At home, I read that Berend Hendriks and Peter Struycken initiated the Arnhem school of environmental art. I do see some similarities in the drawings that were exhibited and the Wetmatige bewegingen works by Peter Struycken.

After the visit to the museum, we visited Antiquariaat Van Hoorn (at Houtstraat 35), a bookshop with second hand books. We also paid a short visit to an underground bike shop where the remains of an old defense tower are revealed. It is called the lost tower, because there was no record of a tower at that location. The tower was part of a second ring of stone walls and towers around the city that was believed to have been build but for which never any evidence was found.

We had a dinner at Thibea, were we ordered the following dishes:

Afterwards, we walked through the city to look at the remains of old medieval and Roman walls on the river side of the town. I walked the labyrith at the river side from the inside to the center. While standing at the center, I heard my own voice bouching of the round walls of the labyrith. I cheated on the way out.

Wednesday, May 18, 2022

Fort Pannerden

Conny and I visited Fort Pannerden, a disused military fort. We learned something about the history of the area and the fort. The audio tour was quite interesting. It took us about two hours to walk through the fort and listen to all the stories. In the middle of the tour we saw an exhibition of woouden sculptures by Will Schropp. We also bought two metal mugs. Next we walked to the end of the dam where the Bijlands Kanaal splits into Pannerdens Kanaal and the river Waal.

Thursday, May 19, 2022


Conny and I went to Arnhem. We first went to Museum Arnhem. From the exhibition consume by, I found the following works interesting: From the exhibition from left to right, I liked the following works: From the exhibition open, I liked the following works: From the sculpture exhibition in the park of the museum, I liked the following works:

After the visit to the museum we walked along the Roemondsplein (square) were the environmental artwork De Blause Golven (The Blue Waves) by Peter Struycken can still be seen in its original state. At the border of the square there is a large sign about the reorganization of the square. This will also involve changing the art work by changing the ratio between the width of the blue and white stripes.

We spend some time in the bookshop De Colofon. At 14:54, I bought the book Theo van Doesburg: oeuvre catalogus written by Theo van Doesburg, Els Hoek, Marleen Blokhuis, Centraal Museum, and Rijksmuseum Kröller-Müller, edited by Els Hoek, illustrations by Theo van Doesburg, written in Dutch and published by Centraal Museum in 2000, ISBN:9789068682557, for € 28.50.

Shortly after three, we arrived at St Eusebius' Church. We walked around the mostly empty church before we were allowed to go up into the tower. The tower was closed due to some bad weather conditions. (Later we discovered that damage caused by thunderstorms in some eastern parts of the country including Enschede were we live.) We dared to walk onto the two glass observation balconies at a height of 59 and 62 meters and took some pictures from them. There was also an audio tour about the Operation Market Garden and the destruction of the church.

After our visit to the church, we walked around a bit, and around five arrived at the Indonesian restaurant Rasasari. We both had a big rames dish where you can make a selection of ingredients to be used. Conny selected rendang beef, tumis beans, gado gado with yellow rice. I selected ayam semoor chicken, atjar, orah areh with fried rice. The dishes also came with a boiled egg, tempeh, fried coconut and crispy potato. We both liked these typical Indonesian dishes.

Thursday, May 26, 2022

Forward button presses to FPGA

Today, I have done some work for the firmware for the MCH2022 badge. I worked on the issue for sending button presses to the FPGA. I managed to get a working solution. I needed to install the pyserial in order to run the Python script for uploading bitstream to the badge. I extended the script a bit for debugging purposes. I was using the following command:
python3 /dev/ttyACM0 buttons.bin

Saturday, May 28, 2022

Into the city

This afternoon, I went into the city. I first went to have a look at the exhibition Ergens in het midden... with portrait and nude photographs by Ragnar Gischas. I was impressed by the pictures and found them artistic. There was also a book with some pictures from the exhibition, but for some reason the prints in the book looked less artistic and more nude. Reason for me to not buy the book.

I walked through the city and went to bookshop Broekhuis where I found a large collection of autobiographic books from Privé-domein ("private domain") series. At 15:50:49, I bought the following two books:

This months interesting links

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