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The China Labyrinth puzzle
This evening, I used the laser cutter at TkkrLab to create a puzzle (using a SVG
file) based on the The China Labyrinth. Below a picture of the pieces (except for one):
One of the members tried to put the pieces inside the frame where the pieces
were cut from, but failed. There are somewhere between 10^20 and 10^22
solutions to the exact cover program that I use
to estimate the number of solutions. On August 16, I already developed the
program hexapuszleSQ.cpp to
generate the input for exact cover program and to generate an SVG file when
given the filename of the file with the solutions.
Puzzle piece shape designer
Yesterday, a member of TkkrLab suggested that I should
have made the pieces of the puzzle into jigsaw pieces that actually stay
together when locked in. I got this idea to make the shape out of connecting
arcs and made a took to select design it. The tool is given below. The green
line indicates the side of the piece. The grey lines connect with the three
points defining the shape. The points can be moved by clicking with a mouse
and drag them around. The radius of the middle arc can be adjusted with the
slider. When this results in an impossible shape, a message is shown in the
output window. The red lines shows the calculated lines for the connecting
circle to the ends of the side. The output shows the radius and postions of the
three points as percentages of the length of the side. It also calculates the
area above the the side substracted by the area below displayed as a
percentage.
Some notes used for calculating the position of the red lines:
a^2 + (b + x)^2 = (r + x)^2
a^2 + b^2 + 2bx + x^2 = r^2 + 2rx + x^2
2(b - r)x = r^2 - a^2 - b^2
x = (r^2 - a^2 - b^2)/2(b-r)
FLT has been formalized in Lean
Today came the news that FLT has been formalized in Lean by Claude, the AI agent by Antropic. FLT is short of Fermat's Last Theorem,
a famous proposition for which the French mathematician Pierre de Fermat arounf 1637 claimed that he had a proof but that the
proof was large to fit in the margin. Many mathematicians since then have tried
to proof it but it was only in 1994 until Andrew Wiles proved it and formally published it in 1995. Lean is a
mathematical proof assistant and a functional programming language. There are
several other such proof assistants, but currently, Lean is the most popular.
FLT is also the final theorem to be formalize in Freek Wiedijk's famous
list of 100 formalization
challenges and wraps up this 20-year=old benchmark. Lean has become the
proof assistant that is being used to (dis)proof mathematical propositions and
hypothesis with the help of AI agents. There was already work on the way as
part of the Xena project to
formalize FLT in Lean, but now Kevin Buzzard wrote the blog FLT: Anthropic has beaten me to it. But he goes on to explain that
although it is a great achievement, the prove does not follow the proof given
by Willes, which the Xena project wants to formalize and also make a dynamic
document enabling humans to explore the proof. The proof that Clause produced
consists of 13.4 million lines of code and Antropic is probably not going to
work on making it human readable. It is definitely helping the progress of
mathematics now that AI agents are helping to formalize proves in statements
that can be automatically verified and push the use of proof assistance such
as Lean.
Simple Modbus storage server
In the past week, I have been working on a simple server for the Modbus protocol. The server implements a memory store. For a commercial
project I am working on, I have to implement a Modbus client that talks with
some Modbus server. Because I want to test whether this client is working
correctly, I decided to implement a simple server on an ESP32-S3 microcontroller using ESP-IDF with PlatformIO in the
intergrated development environment Visual Studio Code. I also took it as an opportunity to experiment with
the TinyCoPoOS
operating system that I developed almost two years ago and mentioned on
November 17, 2024. I have finished
implementing this in the repository ModbusClient for the 'native' environment with unit-tests, which means not
yet actually tested on an ESP32-S3. That will be next step. I have made some
changes to the TinyCoPoOS operating system that I publised about two years ago
and pushed those to the repository.
Going into the city
I biked into the city with just a shirt because the temperature was around
21° Celsius. At photogalary Objektief, I saw the exhibition De Adem van de Aarde (in English: The Breath of the
Earth) with (digitally manipulated images from) photographs by August Langhout. From there I walked to the galery Beeld & Aambeeld where I saw the exhibition A Transatlantic
Meeting with paintings by Maike Eilers and jewellery by Jillian Moore. I found the paintings interesting but a bit too constructed
as if the artist first creates a digital manipulated image from pictures taken
from nature and then makes a painting of it. I had a quick look at Concordia
where there is a group of four recently graduated international artists who
work on site-specific installations for the GOGBOT festival which opens next Thursday evening. There was not much to
see except two of them working. I walked through the Grote Kerk (Great Church),
which was open due to the European Heritage Days this weekend. It is the oldest building of the city
of which the oldest parts date from around 1200.
The path in SVG uses a different method for specifying an arc than JavaScript.
In JavaScript you specify the coordinates of the center, the radius, the start
and end angle and whether it clock-wise or counter-clock-wise. In the path
command in SVG you can use the 'A' command to draw an arc from the current point to the next
point specifying the size and orientation of an elipse (with three parameters)
and the flags 'large-arc' and 'sweep', and of course the coordinates of the
next point. I also realized that if you want to cut the pieces with a laser
the width of the laser beam is probably two small to make the pieces fit
easily and that you might want to specify the gap between the pieces. With
the below you can specify gap. In the output it produces the values needed for
generating the arc commands in SVG in the form of some code that can be
included in a C(++) program. The position of the points are marked with a dot.
Again going into the city
I first went to Sickhouse where I went
to see, or better, experience the immersive installation Dérive by Alexander
Zanen, where you wearing headphones and a tracker move through the room
while listening to a story. Although I am more of a visual person than an
auditorial person, I did like it. Next, I went to Craft District Enschede to attend the volunteer meet-up for GOGBOT. On the way home, I went to Het
Robson, which was open as part of the European Heritage Days. I saw the exhibition Diana Huijts with works by her. I have a book with prints from her series of lino prints about the
alpha tower (the highest building in Enschede). I was a bit surprised by the
great variation of techniques that were used for all the other works on
display. I also talked a bit with the artists Jet Broekstra and Mark van Loon
from Beeldbouw.
Free stuff
Someone at TkkrLab was cleaning two of his
Samla boxes and donating things. I got the following items:
- SCT013 from YHDC in box.
- OPN-2001 from Opticom.
- Small PCB with three 7-segement displays and a LED
- 3621AS - 0.36-inch Red 2-Digit CC LED 7-Segment Display.
- Two CC25XX Zigbee USB dongles in 3D printed cases. (One came with an
antenna that another member took with him.)
- Canton-Power DDO603SA buck converter
- SanDisk 4GB DDHC Card
GOGBOT: Day 1
This evening, I volunteerd as an art guardian at Sickhouse for the GOGBOT Festival. There, I saw the following art installations:
GOGBOT: Day 2
This afternoon, I visited various locations that are part of the GOGBOT Festival. I first went back to Sickhouse to see the performance by
Mythe van Loon in her installation:
Paultaar - This Is Our
Church - Make It Fucking Louder. I was quite interesting and enjoyable.
At Rijksmuseum Twenthe, I saw the exhibition Democracy Now. I found the following noteworthy:
- NOS Fake News, ViaOral, 2021.
- Inflammatory, Jenny Holzer, 1979-1982.
- Winst boven vrede | Profis over Peace, Umar Rashid, 2022.
- Propgagnada Theater, Video Study, Jonas Staal .
- Hate Breed, INDECLINE, 2019.
- APE, Seán Hannan, 2023-2024.
- L'État, c'est moi, Johannes Büttner, 2026.
- Untitled (Sword Dance), Erik van Lieshout, 2017.
- Masse | Masses, Peter Zegveld, 2018.
- Vox Populi, Peter Zegveld, 2018.
- Dolls vs. Dicators, Martha Colburn, 2010.
- Untitled, Erik van Lieshout, 2017.
- I want a President, Marina Naprushkina, 2021.
- Dialogues with the Future, Ursula Biemann, 2026.
- AI War Cloud, Sarah Ciston, 2024-ongoing.
- The Chronicle of Gaia, Carlijn Kingma, 2019.
- Nouveaux voyages de Mr le Baron de Lahontau, dans l'Amerique
Septentrionale (book), Louis Armand de Lom d'Arce Baron de Lahontan,
1703
At TETEM art space, I saw:
At the Oude Markt (square), I walked through the 12×12×12 meter
GOGBOT ALIEN CUBE and saw:
At Concordia, I watched a short video about the three-week GOGBOT x Concordia
Productielab residency and I saw the results:
At the Grote Kerk, I saw:
At Concordia (Cinema), I saw the installations and films:
- preconditions (In
Medio), Sanne Scheepmaker.
- Fanfictional
Politics, Pedro Gossler, 2022.
- I Am the Film Motherfucker, but I'm Real (film), Meowx2, 2026.
- The Hero (film),
Marina Abramović, 2001.
- Patriotic (film),
Benny Nemer, 2005.
- Heart Paper
Transfer (film), Tamarma
& Yamadatesla,
2026.
In the evening, I volunteerd as an art guardian in the Grote Kerk.
GOGBOT, Day 4
In the afternoon, I went to the city to join the GOGBOT festval again. At Concordia (Cinema), I saw:
Next, I walked around the Oude Markt and has a short look at Live Radio Broadcast by Radio Echo
Collective and I went to tower of the Grote Kerk to meet with Albert van de Weide again, who has been painting, as a kind of performance,
small paintings with the text Alle macht aan de kunst (Dutch for All
power to art. He painted twelve each day, with slightly different
colours and typography each day. He was handing them out to visistors and he
was so kind to give me one as well. I went back to
Concordia (Cinema), where I watched:
I went to Metropool, the only locations had not visited yet, the volunteer
again as an art guardian. There I saw:
After the festival closed at 18:00, I helped a bit cleaning up the main area
around the Oude Markt and also had some dinner. When I biked home, I made a
small detour and collected five chestnuts from
a tree in front of a Chinese restaurant 'Oriental City'.
The China Labyrinth puzzle
This evening at TkkrLab, I made some attempts
to create a jigsaw puzzle from polymethylmethacrylaat based on the The China Labyrinth following a suggestion made by another member three weeks ago. I used the tools I shown with Puzzle
piece shape designer and SVG for puzzle pieces for
the a new version of the program hexapuszleSQ.cpp. My first attempt was with a rather large gap
between the pieces. The gap proved to much to wide. I also discovered that it
had some the same pieces, which should not be the case. I decided to add the
I Ching hexagrams. For the
second attempt, I reduced to a quarter. Because I had spend a lot of time
removeing the protective plastic film from each of the pieces of the first
attempt, I decided to remove the film before cutting. This turned out not such
a good idea, as the pieces had brown spots and had dull spots. I also felt that
there was still too much space between the pieces. For the final attempt, I
used the SVG shown below. I was
satisfied with the result.
This months interesting links
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