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Around 11:10 this morning, I colleague remarked that there was some
snow outside. I indeed saw some small specks
of snow. A little later, real snowflakes were falling from the sky,
but none of snow stayed on the ground.
Last Saturday, I read a story on Slashdot about the book
10 PRINT CHR$(205.5+RND(1)); : GOTO 10, which is about the
one-line Commodore 64 BASIC program given in the title that generates
random diagonal mazes. Watch
this YouTube movie about the execution of the program. There are
two ways to interpret the generated pattern. I looked at the light blue
lines as walls. Below, I have given a similar output, but with a non-random
border around it, where the walls are drawn in black on white background.
(A new one will be generated on reload.)
When I saw this, I almost immediately asked myself, what would be the average
length of your walk when you would land somewhere? There are many short walks,
but also some much longer walks. What would be the length if the image was
infinite in all directions? Could you land in an infinite walk? I paged through
the book (which can be downloaded freely) and did not find any of these
questions being addressed.
You can also look at the dark blue parts as walls. Below gives some output
where the light blue parts are made in much wider pathways and there are walls
added on the side.
Now you could ask yourself the question of what is the chance that there
is a path from the top to the bottom for every given height with a given
width. Of what is the chance if you start somewhere on the top, you can
reach the bottom? When I posed some of these questions on Slashdot
someone mentioned percolation theory.
Below a random labyrinth is given, where there is always a path from
the entrance at the top to the exit at the bottom. The inside is purely
random and a new one will be generated on each reload of this page. At
first it might sound surprising that this is the always the case, but
once you realize that there are no splits in this mazes (and thus would
be called a labyrinth by many), it must be the case that starting from
the entry you must arrive at the exit somehow.
If you create another pair of exits on the sides of the mazes it must be the
case that if you enter from the top, you must exit at one of these exists.
Through the other exit on the side you always arrive at the exit at the bottom.
(You can never arrive at the bottom, because that would mean that the exits
at the sides are connected and that somehow the two walks must cross some where.)
In a sense this is much like the basic unit of this random maze. This means
that each diagonal bar from a maze can be replaced by a random labyrinth with
four exits. Below six smaller random labyrinth are give that could serve as
building blocks. This suggests that there is some scale invariance at play. This may also hint at some of the other
questions I have been raising.
Children of Dune
Today, I finished reading the Dutch translation of
Children of Dun by Frank Herbert, which I started reading on November 11.
The day before, I bought the book from bookshop Kruimeltje for € 5.00. This is the third time, I read
this book, but to my knowledge, the last time was more than thirty years ago.
What I liked most about the book is the intricate plot where multiple (groups
of) people are making plans to gain (or keep) power, and how all the plot
develops. I was a little dissapointed about the last two chapters. The last
chapter I found rather pedantic. I found the manner in which Herbert finishes
the story in the forelast chapter not very subtle. What I remember from the
miniseries that was based on this book, is a far more elaborate ending.
During the night about 1 cm of snow fell. But it did
not stay everywhere on the ground. During the morning there was a little snow.
At some place the snow stayed during the day. More snow is predicted for the
In the morning, it snowed again. At the office, we
saw the snow fall almost horizontal due to the strong wind. It snowed quite
strong for some time and the snow did stay after some time. During the
afternoon, some of it melted again.
I got a flat tire while biking into the city. Here a close-up photograph
on a 1cm grid sheet of paper of two pieces of glass that I found in the
outer tire. I found a hole matching with one of the glass made holes,
most likely the one that the white piece of glass came from.
Today, is again one of these special dates: A same number date. It is also twenty years ago that Li-Xia and I started dating.
The Hobbit: An Unexpected Journey
This evening, I went to see the movie
The Hobbit: An Unexpected Journey with three colleagues
of mine. We watched the movie in the new HFR format. Some people
report that they are annoyed by it, but I did not. I found the first
part a little boring, thinking that I would not want to see the
remaining two movies. In the second half of the movie, I felt that
the story finally got off, making me want to see the other stories
as well, not in the first place because of all the action, but
because of the drama. I cannot remember having read the book myself,
so I could not judge to what extend the movie was true to the
original story. At home I did check some parts a Tolkien lexicon.
I had never heard of Radagast the brown, but he proved to be a real character.
However, I found him riding on a sled pulled by rabbits a little
a little out of place.
Today is a double date when the date is
written in the format DD-MM-YYYY: 20-12-2012. The next such date is on
January 21, 2101. I think it is safe to say that it will be the last of my
I looked at the reproduction of Komputerstrukturen 3a by Peter Struycken
in P. Struycken komputerstrukturen
from 1970. I wrote a script for the MySample
editor to analyze the reproduction and estimate the most likely input for
the OSTRC program that was used to generate it. This program counted the
following number of codes per column (of two by two black/white squares):
column 11 13 23 24 25 33 34
1 7 8 10
2 1 8 8 8
3 8 6 10 1
4 1 9 5 8 2
5 13 5 7
6 8 9 8
7 9 7 9
8 7 9 9
9 9 7 8 1
10 7 15 3
11 8 10 7
12 15 6 4
13 9 8 8
14 6 12 7
15 7 12 6
16 5 11 9
17 7 11 7
18 7 11 7
19 6 12 7
20 1 9 8 7
21 11 6 8
22 9 7 8 1
23 1 6 5 12 1
24 6 10 9
25 8 6 11
Furthermore the algorithm concluded that an equal distribution of the
codes 23, 24, and 25 was the most likely. Knowing the number of errors
in the reproductions of Komputerstrukturen 1a
and Komputerstrukturen 4a, it is likely that
the 10 out of 625 different codes are caused by errors in the reproduction.
Under the assumption that each different code is caused by a single
reproduction error, a code 11 could have been a code 24 or 25, a code
13 could have been a code 23 or 25, a code 33 could have been a code 23,
24, or 25, and a code 34 must have been a code 24. This means (under the
given assumption) that we are only sure of one reproduction error. One
could argue that some error is more likely to have occured than others,
but taking into account that column 10 has only three codes 23, it seems
that the changes are not far apart. The list of (possible) reproduction
errors is (where columns and rows numbers refer to single black/white
- Row 1, column 45: changed black to white or
row 2, column 45: changed black to white.
- Row 4, column 3: changed black to white or
row 4, column 4: changed black to white.
- Row 7, column 17: changed white to black,
row 8, column 17: changed white to black, or
row 8, column 18: changed white to black.
- Row 9, column 39: changed black to white or
row 10, column 39: changed black to white.
- Row 23, column 46: changed white to black.
- Row 29, column 43: changed white to black,
row 30, column 43: changed white to black, or
row 30, column 44: changed white to black.
- Row 43, column 7: changed white to black,
row 44, column 7: changed white to black, or
row 44, column 8: changed white to black.
- Row 47, column 5: changed white to black,
row 48, column 5: changed white to black, or
row 48, column 6: changed white to black.
- Row 48, column 7: changed black to white or
row 48, column 8: changed black to white.
- Row 49, column 7: changed white to black,
row 50, column 7: changed white to black, or
row 50, column 8: changed white to black.
The limited sale at bookshop De Slegte is
only 30% off for the price for which the books were sold first. As far as I
can remember reductions where always at least 50% and often books were sold
for ridiculous prices. For me this is one more sign that De Slegte is changing
into a regular bookshop under the control of the new owner. I bought the
book De schoonheid van de man (The beauty of the man) by
Florence Ehnuel (ISBN:9789023435938) for € 5.99.
I compared the reproduction of Komputerstrukturen 4 by Peter Struycken
in P. Struycken
komputerstrukturen, in P. Struycken (illustration 10 in the introduction and illustration
30 on page 36), and the image given on the website of Stedelijk Museum Amsterdam, where it
found under the name "Computerstructuur IV A, 1969". I found that the
reproduction in P. Struycken komputerstrukturen contains the following
differences compared with the other two:
- Row 4, column 41: changed white to black.
- Row 4, column 42: changed black to white.
- Row 8, column 6: changed black to white.
- Row 8, column 25: changed white to black.
- Row 8, column 27: changed white to black.
- Row 8, column 35: changed white to black.
- Row 22, column 11: changed white to black.
- Row 22, column 12: changed black to white.
When walked to the entrance of the nursing home, Li-Xia
seemed to recognize me, because she stood up and/or walked closer to the
window. It has been a long time ago, I saw her do this. She was still in
her pyamas because she was going to have a bath in a Snoezelen room. Around half past nine, I walked with her and two people
from the nursing home to the bathroom where there were only coloured lights.
Furthermore there was a nice smell in the air and there was soft music being
played. She was lifted in the bath with a lift attached to the ceiling and
which can move freely in all directions. The water was a body temperature.
First they washed her hair and then they switched the ultrasone cleaning on
for 10 minutes. And after another 10 minutes in the bath they lifted her out
of it and we dried her and put on her clothes. Back in the common living
room her hair was dried. It was nice to do this with Li-Xia who seems to
enjoyed it very much. I stayed for tea and a oliebol, a traditional Dutch treat for new years eve. Before I left,
I also bought some of them downstairs where they had baked three thousand
I went home throught the city center and at bookshop De Slegte I bought Gesprekken met Simone de Beauvoir
(Interviews with Simone de Beauvoir) by Alice Schwarzer,
ISBN:9789067660273, for € 0.50.
This months interesting links
| November 2012
| January 2013
| Random memories