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
|
Are street tiling patterns Turing complete?
Today it is 56 calendar years ago that I was born, which means that I am born
on a Wednesday. This is because 56 is twice 28 and it is a property of
the Gregorian
calendar that the days of the week repeat after 28 years (except when
there is a century crossing involved that is not divisible by 400). I did not
really celebrate my birthday.
Last week, I wondered whether it is possible to generate a possible infinite
street tiling pattern without using back-tracking.
I thought about starting with some row of a certain length and next generate
rows below it as long as I wished. I was thinking about putting this into a
JavaScript script inside a page and generate a random pattern on demand. I
worked on a program to generate all
impossible sequences to be found in a row and all impossible continuations from
a part of a row to the next row. I think the program is correct, but I do not
know how to convert the output into a state machine for generating a 'random'
row below a given row. I even do not know if it is possible. Than it appeared
to me that maybe Street tile patterns might be complex enough to be
Turing
complete.
Walking Through Walls
Early this morning, I finished reading the book
Walk Through Walls: A Memoir by Marina Abramović and James Kaplan (as ghost writer, it seems), which I started reading on
October 14 after I bought it on October 11. I
actually really started reading the book from October 24. I found this quite an
interesting book, mind blowing at moments. It made me also realize how much I
already knew about her, first through the book The lovers, which I
bought many years ago and also read, and later also through watching some
videos about her and her performances. She also talks about her personal
struggles and the many retreats she undertook remote areas, with Australian
Aboriginal peoples, at buddhist monastries, and with shamans in the amazone.
Many of these she describes as life changing. She also descibes her struggles
when her second husband Paolo Canevari leaves her, actually twice, to a women who described
herself as a sexual anthropologist, a woman with dead-white skin
and red hair. Betony
Vernon matches this description and there are also photos of her together
with Paolo Canevari. However, from 2004 to 2014, Vernon was married to Barnaba
Fornasetti. Canevari met with the woman at the Givenchy show in 2008 and in
2010, Abramović talked with the woman against the will of Canevari
after he had returned to her. The woman told her: "He's addicted to me. He will
always come back to me." And that is what happened. Probably the woman
understood male sexuality better than Abramović, that she could make this
statement.
Bottle ring
This evening at TkkrLab, another member made
a bottle ring with the text ffaa5e with the of Blender and one of our 3D printers. The result is show on the top right.
Infinite sequences
I discovered that my statement about street tiling
pattern of the first of the month is incorrect. When
I increased the length of the sequences to be investigated (with this program), I discovered that it did not stop at what I had thought.
It seems the list of impossible sequences and chains is infinite. (A chain
consists of two sequences that match with valid tiles.) I studied the
impossible sequences for a general pattern, but did not discover one. I did
noticed that sequences and chains where not really symmetric and realized that
this has to do with the encoding method of the street tiles, which all start
with an 'A' in the left top corner. This gave me the idea to give each street
tile its own encoding letters, using the following encoding:
a bc
d fg jkl
e hi mno
pq ABC
rs DEF
tu GHI
This resulted in only a
limited set of chains (only with length two) to be impossible. But it seems
that there are still infinite impossible sequences. I started visualzing the
sequences with embedded JavaScript below and
only leaving the characteristic sequences:
It looks that for each length, there are only a limited number of patterns, if
we look at the the depth at which the piece extend down. I have selected one
pattern for each of them. I also worked on constructing a grammar (so far only
a regular expression) to match all the patterns.
Bike stolen
At 17:30, I arrived at thrift store Het Goed
and looked around the book section. When I came outside around 17:50, my Urban
HPV bike, which I got on Wednesday, March 9,
2011, was gone. I spend some time looking around, considering the
possibility that I was mistaken about the place wheren I had placed it. I went
inside to ask if it happens more often that bikes are stolen in front of the
shop. They had only heard about an electric assisted bike being stolen. The
bike was already getting old, but at the beginning of the summer the
transmission had broken down and was replaced by a new one. I was counting on
using it for another three years before it being replaced. I have not much
hope of getting the bike back, as usually they are transported to East Europe
and sold there. I did report the bike as being stolen when I arrived at home.
I will miss all the extra things: The two horns (on a gift from Annabel, the
other found in the attic), the three induction lights, and the two yellow
CYBER stickers.
Open day AKI
In the afternoon, I went to the AKI. Outside I
ran into a friend, who in the past studied at the AKI. We decided to attend the
open day together. First we went to the media center and library. Outside there
was a table where the sold old catalogues for € 5. At 14:04, I bought
the following two catalogues:
At the photography department we looked inside the dark room, and the friend
took a picture of me with the 8x10 camera on photographic paper. We went to
dark room again, to see how it was developed. While it was being rinsed, we
looked around the students rooms with paintings and other works of art. We
did see some promissing work, but because the students were not pressent, it
was not possible to talk with them. When the photograph was ready, it was
scanned and I received a print (after it inverted). Two teachers were posing
and giving assignments. I also made two 'drawings' with a brush and indian ink.
I took some pictures of the teachers, especially when they were performing a
slow motion dance. At the end we had our picture near the entrance holding a
frame with the text: AKI OPEN.
HEMA puzzle
Last month, I calculated the number of
solutions for the HEMA puzzle, but what I had not taken into accound, was the
fact that some of the wooden pieces of the actual puzzle do not fit, simply
because the part that should fit in a 'gap' of another piece, is not small
enough to fit. I made some analyses of all the possible combinations of
pieces that require a physical constraint in all the solutions (using
this program) and added that information
below. I named the pieces according to the names given by
Name that Color. (The
name of the pieces is displayed as a tooltip in the displayed solution below.)
You can indicate which of the pieces do not fit and see which solutions you can
actually make. The initial values are for the my instance of the puzzle.
Booklets and map
At 11:56, I bought the following booklets and map from thrift store Het Goed:
- black and white and sometimes colourful no2 written by dr. Rebeca
Galera de Toro written in English for € 0.95.
- eigen verzameling zomer 1969 | permanent collection summer 1969
written in Dutch and English and published by Stedelijk Museum Amsterdam
in 1969 for € 0.50.
- Rut Bryk, Catalogusnummer 481 written by Lisa Licitra Ponti in Dutch
and English, and published by Stedelijk Museum Amsterdam in 1970 for
€ 1.50.
- Map moderne architectuur in zestien landen van
europa by István L. Szénássy. Attachment with
Museumjournaal serie 13 no 4, 1968. Size 70 by 85 cm. For € 1.50.
- Omdenken written by Berthold Gunster in Dutch and published by
Ja-maar® for € 1.50.
Broese
I had the opportunity to visit Utrecht for some hours. I went to bookshop
Broese Boekverkopers and arrived there a
few minutes before they opened at noon. I was the second customer entering the
store. I looked around a little, and at 12:04:14, I bought the book Boud:
het verzameld leven van Boudewijn Büch (1948-2002) (a biography about
Boudewijn
Büch) written by Eva Rovers in Dutch and published by Uitgeverij
Prometheus in 2016,
ISBN:9789035137424 for € 5.95. I looked around some more and found
some interesting book, but decided to have a look at the bookshop Steven Sterk first. I did not buy anything there. I returned to Broese
Boekverkopers and at 13:28:19, I bought the book The
Philosophy of Andy Warhol: From A to B and Back Again written by Andy
Warhol in English and published by Houghton Mifflin Harcourt in 2014,
ISBN:9780547543437, for € 8.00. I also bought a Moleskin daily planner for 2018 for € 18.90. At home I
discovered that it was the soft cover edition. I have used hard cover edition
in the past years.
Agile software development
There are two ways you can read 'agile software development' depending on how
you place the brackets. You can read it is as 'agile (software development)',
which is about the software development process, and you can read it as
'(agile software) developement', which is about the code and the cost of
change. Most people read it in the first manner, and it seems that the second
manner is almost forgotten. Even on the eXtreme Programming there is more focus on the process than the software,
as refactoring is only first mentioned under the heading 'Courage', while it
one of the essential techniques to avoid the exponention growth of cost of
change over time. The whole idea of eXtreme Programming was to keep the cost of
change down, by avoiding rigidity of the code base, by keeping the code base
agile. Without a focus on the agility of the software an agile software
development method will fail in the long run. At the start of a new project, it
is still easy to produce new functionality and impress a customer with the
effectiveness of an agile software development process, but in the long run, it
is no guarantee for the maintainability of the software.
MINIX3
This evening, at TkkrLab I wanted to install
MINIX3 on my notebook. Some weeks ago, I
had made some attempts as well, but those did not work because the MINIX3 does
not support USB. I had read somewhere that somebody used
KVM to
boot an ISO image. However, when I ran pacman, I discovered that my
32-bit Arch Linux installation is no longer supported. When I talked with some
member, they noted that probably KVM does not work on my notebook, because
most Atom processors do not support Intel® Virtualization
Technology. And it appeared mine did not. There is still the option to use
QEMU. I decided to at least
start with a minimal installation of
64-bit Arch Linux.
This months interesting links
Home
| October 2017
| December 2017
Tuesday, November 7, 2017
Saturday, November 18, 2017