## I write, therefore I amWith 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. | |||

## Sunday, June 26, 2016## JellyfishThe tweet Will each jellyfish in this GIF eventually end up where it started? with a GIF by Frédéric Vayssouze-Faure encouraged me to write a program to analyse this GIF. Of course, as there are only a finite number of states, at some point all jellyfish will be at their starting location. But how many swim movements will it take. I used GIF maker to retrieve the movements. I already had noticed that there were three types of swim movements that were repeated over and over again. I encoded these in the program with the characters '>', '<', '^', 'v', and '|'. The latter I used to replace '^' and 'v' when I realized that it is always possible to derive which one should be used. The program quickly found that after 6192 swim movements all jellyfish have returned at their original location. Vayssouze-Faure placed the remark: "If I had the time I would check if one of them can reach the bottom from the top…" After 23 swim movements the first jellyfish from the fifth column arrives at the top left corner. After 197 swim movements there are six jellyfish from the bottom at the top row. This is the configuration using hexadecimal digits from the row and the column:
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f we look at where the jellyfish each time the three swim movements have been performed, it turns out that there are eleven different sequences, which when marked with the letter 'a' to 'k', results in the following table:
a a a a a a a a a a b a c b a c a a a a a a d a a a c c b c c b a a a a d d d a c a a e e c a a a a a a a a a a e a c a a c a c a a a a a a f a e f e e e a a a a a a a f a f f a a a a e a c a a f f a f f a f f a a a a a a a a a a f a f f a a f a a a a a a a f g a a a a a a a a a a a a a g a g a a a a a a a a a a a a a a a g a a a a a a a a a h i i h a a a a a a a a a a h h i h h i a a a a a a h a a h a j h h h a a a a a a a a a h a k j h j h h a a a a a a h a k a k j h h h h a a a a a a a a h a k h a h h a There are six sequences ('b', 'd', 'g', 'i', 'j', and 'k') with a length of 12 swim movements (where the letter of each sequence appears four times in the table), a sequence ('e') of length 24, a sequence ('c') of length 36, a sequence ('f') of length 48, and a sequence ('a') of length 516. The least common multiplier of the lengths is 6192. Actually, this is the least common multiplier of 516, 72, and 48. The real big question is if there exists a combination of three swimming patterns with an even larger repeat length. It seems that the jellyfish never make a complete turn from one swimming pattern to the next. (I have not verified this with the program.) It seems a good requirement to imposse on combinations of swimming patterns. Of course, one could also ask this question for smaller sized squares (or rectangles) and with different number of swimming patterns. ## Saturday, June 25, 2016## NovelAt 17:39:14, I bought the novelDe ontsnapping written by
Heleen van Royen
written in Dutch published by Heleen van Royen in 2009,
ISBN:9789049951313, from bookshop Broekhuis
for € 6.00.
## Friday, June 24, 2016## AKI finals 2016In the afternoon, I went to theAKI finals 2016 exhibition. I first
visited Dynamo Expo. Next, I went to
TETEM art space. Finally, I visited the main
AKI ArtEZ building. At 18:01, I bought the book
analoog | analogue | analog edited by Johan Visser written in Dutch,
English, and German published by AKI ArtEZ on Friday, June 24, 2016,
ISBN:9789075522372, from AKI ArtEZ for € 15.00. I found the
following artist interesting:
- Bo Lamers. A large self-portret is reproduced on the outside of the building. She also had a collage of painting and drawing, which I found less interesting.
- Annejet Riedijk. She had two videos and five paintings on display. I find her painting style very interesting. In a sense it is very vague and with odd colours, but yet it looks very realistic, almost like you watching reality through a kind of filter.
- Marcel Berwanger. He had a sketch book with experimental calligraphy that looked very interesting.
- Ilse Löbker. I found her
*Vertaalconcept*(*Translation concept*) rather interesting. - Joyce Rothman. Her combination of
linocuts and poems under the title
*Vluchten*(*fleeing*) was interesting. - Rahel Kausemann. I liked her design of her master thesis.
- Dieuwke Eggink. I especially found his three paintings of the same scene with different colours interesting.
- Huub van Stijn with his
*Atlas of Desolation*consisting of large sized book, a small booklet and a wall painting.
## Tuesday, June 21, 2016## Link## Saturday, June 18, 2016## Small magnolia treeour small magnolia tree has survived the frost period from early May. It is now about 25 cm tall. It seems that the budds at the top have died, preventing the tree to grow higher. But I notived something near one of the leaves that could grow into a new branch.## Not unabridgedI just searched for the track about the digits pages in Extremely Loud & Incredibly Close on the audio book, I bought last Wednesday. It starts on track 14 of disk 8. I was a little disappointed to discover that they skipped the whole pages of digits after the first 8 on the first full line of digits on page 269. It thought that unabridged meant: "Containing the original content; not condensed". Leaving out almost two and half pages of text (arguably very boring text, that no one would have actually read) does not feel like: original content. Also the condensed text starting from "I've seen him" on page 281, which is still readable for the first lines, has been left out at the end of track 6 of disk 9.## Friday, June 17, 2016## Link## Wednesday, June 15, 2016## AmsterdamAround 11, I arrived in Amsterdam and went to bookshop Scheltema. I bought the audiobook (consisting of 10 audio CD's Extremely Loud & Incredibly Close, ISBN:9781464009136, for € 8.90 and the catalog of exihibtionInvisible Poem, ART LABOR Gallery, Shanghai, China with works by
Lu Xinjian for
€ 8.00.
Around 1 in the afternoon, I arrived at the Rijksmuseum where I met with Meindert. I first wanted to go to Room 3.4. Before getting there we saw three paintings by Karel Appel and a video of Imponderabilia by Marina Abramović and Ulay. In Room 3.4, I first went to look at the works: *Dish Relief*by Jan Schoonhoven, 1963.*Relief with Segment*by Ad Dekkers (1938-1974), 1967.*Variation on Circles IV*by Ad Dekkers (1938-1974), 1965 - 1967.
*Splash*by Peter Struycken, 1974
*Bare Bottom Dress*by Marlies Dekkers, in or after 1993- Without title (known as 'postkantoorreliëf') by Jan Schoonhoven, 1958.
- Design sketches for Centraal Beheer building in Apeldoorn by Herman Hertzberger.
*The Crucifixion*by Jacob Cornelisz van Oostsanen, about 1507-1510. (In Room 0.1)- Memorial Tablet for the Lords of Montfoort, about 1400. (In Room 0.4)
*Landscape with an Episode from the Conquest of America*by Jan Jansz Mostaert, about 1535. (In Room 0.4)*The calling of St John during the marriage at Cana*by Jan Cornelisz Vermeyen, about 1530 - 1532. (In Room 0.6)*The Deposition and the Entombment*by 1290. Note 'carpenter' removing a nail from the feet of Christ. (In Room 0.2)*Portrait of a Girl Dressed in Blue*by Johannes Cornelisz. Verspronck, 1641. (In Eregalerij)*Gallant Conversation, Known as ‘The Paternal Admonition'*by Gerard ter Borch (II), about 1654. (In Room 2.25)*Still Life with Asparagus*by Adriaen Coorte, 1697. (In Room 2.24)*Jeremiah Lamenting the Destruction of Jerusalem*by Rembrandt Harmensz. van Rijn, 1630. (In Room 2.8)*Self-portrait*by Vincent van Gogh, 1887. (In Room 1.18)*La Corniche near Monaco*by Claude Monet, 1884. (In Room 1.18)*Portrait of Albert Verwey*by Jan Veth, 1885. (In Room 1.18)*The Singel Bridge at the Paleisstraat in Amsterdam*by George Hendrik Breitner, 1896. (In Room 1.18)*The Voorstraat Harbour in Dordrecht*by Willem Witsen, 1898. (In Room 1.18)*View of the Oosterpark, Amsterdam, in the Snow*by George Hendrik Breitner, 1892. (In Room 1.18)*Wooded View near Barbizon*by Johan Hendrik Weissenbruch, 1900. (In Room 1.18)
## Tuesday, June 14, 2016## Link- SYNTHI-JS is an emulator of the legendary EMS Synthi A modular synthesizer, built in JavaScript.
## Monday, June 13, 2016## More Versaille like patternsIn the past weeks the Street Tilling Patterns program crunched on to find more and more solutions. For size 36 it found a total of 1735 unique patterns. Below, I have given the 74 patterns of size 36 that use the same ratio of kinds of tiles as found in the Versaille pattern, many of which are not laid out in a six by six square pattern as the Versaille pattern.
## Links- Three Gears are Possible - Numberphile
- Sketches by GrgrDvrt
## Monday, June 13, 2016## Link- Three Gears are Possible - Numberphile
## Sunday, June 12, 2016## Kunst in het VolksparkIn the afternoon, I went tohet Volkspark (literally, the people's park)
in Enschede to attend an open art exhibition. I came along the tent of the
art gallery Beeld en Aambeeld and
found that they had some works by Billy Foley on
display. At half past two, I listened to a one hour performance of
Netherlands Symphony Orchestra. I met with several new and (very) old
acquaintances. I also listened to Twents Jeugd Symfonie Orkest when they
started playing "Millenium" by Richard Meyer, which to me has some similarities
with music from Star Wars and The Lord of the Rings. Could have been written
for a movie. (See for example a performance by SC All-State Junior Orchestra 2011.) The GPS-track of how
I walked in KML file for Google Earth or in Google Maps
## Thursday, June 9, 2016## Links## Tuesday, June 7, 2016## BookI recieved the bookAKI 1999 EINDEXAMENS edited by Maarten Binnenhuis,
Sipke Huisman, and Regina Kroeders written in Dutch and English published by
AKI academie voor beeldende kunst en vormgeving in 1999, for which I paid
€ 8.90.
## Monday, June 6, 2016## 7000 Eichen MapAt 9:25, I bought the map7000 Eichen -
Standorte: Ausschnitt der Karte der Stadt Kassel (estimated scale 1:20,000)
at chariry shop Het Goed for € 0.50.
I found this map without price between the art books and someone working at the
shop, suggested that it might have fallen out of some book. I made some remark
about how a map about oak trees in a city could be related to art. He than gave
it a price. But at home, I discovered that the map was about an art project
called 7000 Eichen –
Stadtverwaldung statt Stadtverwaltung by the artis
Joseph Beuys which
he made around 1982 as part of Documenta 7 in Kasselt. I will see if check if
I can find a book about this at the shop and buy it as well.
## Sunday, June 5, 2016## Street Tiling: correctionWhen calculating the number of tilings within rectangles of various sizes, I discovered some serious omissions in the set of initial tiles, invalidating all previous results, like those presented on May 20. The set of possible tiles is extended to:
AA AA AA AA AB AB AB AB AB AB AD AD AD AD AD AD AG AG AG BA BA BA BD CD DA DD AA AB BA BC CA DE AB BC BG CG DA DG AB BC DA AD CD EA BA BC BD BD BD BD BD BD BG BG BG CA CA CD CD CG DA DA DA DA DD DD ED EF AB AG BC CG EA EG AB BC EA FA FD FA FG FA AB BC BD CD BG CG DE DE DE DE DE DE DG DG EA EA EA EA EA EA ED ED ED EF EF EF EF EF AA AB BA BC CA GH AB BC AB AD BC CD HA HD AG CG HA AA AB BA CA HI EG EG EG FA FA FA FA FA FA FD FD FD FG FG FG GH GH GH GH GH HA HA AB BC HA AB AD BC BD IA ID AG BG IA AB BC IA AA AB BA BC CA AB AD HA HA HD HD HD HD HI HI HI HI IA IA IA IA ID ID ID ID BC CD AB AG BC CG AA AB BA CA AB AD BC BD AB AG BC BG The impossible (partial) diagonal sequences are:
AABAG AABBD AABBG AABDG AABEA AABEG AABFG AABHA AABHD BABAG BABBD BABBG BABDG BABEA BABEG BABFG BABHA BABHD CABAG CABBD CABBG CABDG CABEA CABEG CABFG CABHA CABHD CADAA CADAD CADAG CBDAA CBDAD CBDAG BDDAA BDDAD BDDAG CDDAA CDDAD CDDAG AEDAA AEDAD AEDAG CEDAA CEDAD CEDAG AFDAA AFDAD AFDAG BFDAA BFDAD BFDAG CHDAA CHDAD CHDAG AABIDAA AABIDAD AABIDAG BABIDAA BABIDAD BABIDAG CABIDAA CABIDAD CABIDAG However, when calculating the number of (complete) diagonal sequences, it shows that some diagonal sequences have no continuation, in the sense that there is no two longer sequence that is based on it. The smallest such example is the sequence "DAAHIFAAB". Note that this sequence is one of the impossible (partial) diagonal sequences mentioned May 20. There is only one way the top left part can be filled, namely with a three by three in the top corner and two one by two tiles with the longest side touching the left and top sides. When placed in a rectangle, this sequences has 62 different solutions in the right bottom part. However for the next (partial) diagonal sequence there are only eight different ways it is filled for these 62 solutions. When these sequences are extended with an 'A' on both sides, always the first three and/or the last three have no tile available, thus making them impossible for a (complete) diagonal sequence. Longer sequences that start or end with the "DAAHIFAAB" if (and maybe: and only if) they are followed or preceded with the sequence "DEB", which forces an 'A' for the next diagonal. Below the updated table for the number of sequences per diagonal length.
l #dia #pat 1 2 3 4 5 6 7 8 ------------------------------------------------------------- 3 3 3 3 5 6 6 6 7 14 14 14 9 47 47 47 11 140 141 139 1 13 544 658 442 90 12 15 2616 3708 1868 446 260 42 17 15111 25750 8838 3392 1930 539 306 94 8 4 The latest version of the program also calculates the number of unique (with respect to rotations and mirroring) tilings inside rectangles of various sizes. The algorithm first calculates possible combinations of two rows for a given width, and next uses a recursive algorithm to find the number of patterns for a given height. This could be improved with a matrix transfer method and it is also possible to derive recurrence equations for each row (and column) for this table. Although the table is symmetric along the main diagonal, the numbers above and under the diagonal have been calculated independently to verify the correctness of the algorithm. (The output of the program also contains a table with all tilings.)
| 1 2 3 4 5 6 7 8 9 10 ----+------------------------------------------------------------ 1 | 1 1 0 0 0 0 0 0 0 0 2 | 1 1 1 0 0 0 0 0 0 0 3 | 0 1 2 0 1 2 1 4 5 3 4 | 0 0 0 0 1 1 1 0 2 3 5 | 0 0 1 1 2 4 6 12 28 57 6 | 0 0 2 1 4 0 18 33 49 105 7 | 0 0 1 1 6 18 8 77 195 687 8 | 0 0 4 0 12 33 77 166 1204 5135 9 | 0 0 5 2 28 49 195 1204 3217 29733 10 | 0 0 3 3 57 105 687 5135 29733 83306 Below the 166 unique street tilling patterns that fit in an eight by eight square.
## Saturday, June 4, 2016## UTF-8On March 14, I presented a pretty looking function for checking whether a string is encoded with UTF-8. Yesterday, I realized that there is an error in the algorithm when a UTF-8 sequences consisting of multiple bytes is terminated prematurely. This morning, I wrote a program to check an improved version of the function. This looks less beautiful, but that is partly also because of improved checking. This function only checks UTF-8 characters up to four bytes (as is defined by the current standard). The added check (marked with slightly text colour) is that characters represented by multiple bytes actually fall in the range for which that number of bytes is intended. Theoretical it is possible to represesnt every possible value with in the range of valid Unicde code points with a sequence of four bytes.bool valid_UTF8(const unsigned char *s) { while (*s != 0) if ( *s < 0x80 || ((*s & 0xe0) == 0xc0 && (*s & 0x1e) != 0 || ((*s & 0xf0) == 0xe0 && ((*s & 0x0f) != 0 || (s[1] & 0x20) != 0) || (*s & 0xf8) == 0xf0 && ((*s & 0x07) != 0 || (s[1] & 0x30) != 0) && (*(++s) & 0xc0) == 0x80) && (*(++s) & 0xc0) == 0x80) && (*(++s) & 0xc0) == 0x80) s++; else return false; return true; } ## Truck Run 2016Today, Andy and I joined the yearly Truck Run organized by De Tukker Truckers, just like we did two years ago. The GPS-track of how we drove in KML file for Google Earth or in Google Maps.## Tuesday, May 31, 2016## Installing Arch LinuxToday, I became a member of TkkrLab after having visited their open evenings in the past weeks. This evening, I installed Arch Linux with OpenRC from archlinux-openrc-2016.06.01-dual.iso (put on USB stick) onFJF2, Acer Aspire One notebook.
Read installation log for the details.
## Sunday, May 29, 2016## Maker Festival TwenteThis afternoon, Annabel and I went to the Maker Festival Twente. This year it was focused more on children than last year. At the stand of FabLab Enschede we met some classmates of Annabel. They we making wooden bracelet with a laser cutter. I also had one made with my name on it. Annabel has also looked at 3D printers. At the stand of LayaLay we found a small plug-and-play 3D printer of € 700 and at the stand of Make Block Shop we found a waterproof and somewhat flexible cup that was made by a 3D printer in approximately 51 minutes, which costs € 649.55. Annabel was impressed with the quality. Of course, we also spend some time at the stand of TkkrLab. Finally, I build a Noise! synthesizer at the stand of Reverse Landfill. This gave me some more experience with soldering. Some example sounds can be found on sound cloud.## Saturday, May 28, 2016 |
## IntroductionDiariesJune 2016 May 2016 April 2016 March 2016 February 2016 2016 2015 2014 Alzheimer's Disease Trip to China 2010 -- contact -- ## FamilyFransLi-Xia Annabel Andy Honeymoon Friends Others Pictures
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