At 12:24, I received the AE Modular synthesizer
that I ordered on December 30 last year and which consists of:
AE modular STARTER RACK 2 with four additional modules:
FILTER. Last Wednesday, I received an email stating that it was ready for
transport. A closely followed the transport:
When opening the box, I noted that the fout additional modules where already
installed. I played a little with it.
Conny and I continued walking along the
border. This afternoon, we walked through part of the nature reserve
Lüntener Fischteiche. We first returned pole 834 because it Nr.13 of
Dutch trigonometric point 340306 at 52°07'06,25403"N 6°49'21,75993"E.
We searched for Nr.11 (a stone) and Nr.14 (a TP stone), but could not locate
them. Next we continued our search for border
poles: We encountered the following po.es/stones
- We, 24.02.2021, 20:26: The instruction data for this shipment have been provided by the sender to DHL electronically
- Th, 25.02.2021, 12:44: Pick-up at the preferred location was successful.
- Fr, 26.02.2021, 20:35, Augsburg, Germany: The international shipment has been processed in the parcel center of origin
- Mo, 01.03.2021, 03:55, Dorsten, Germany: The international shipment has been processed in the export parcel center
- Mo, 01.03.2021, 17:11: The shipment has arrived in the destination country/destination area
- Tu, 02.03.2021, 08:09: The shipment is being prepared for delivery in the delivery depot
- Tu, 02.03.2021, 11:04: The shipment is being prepared for delivery in the delivery depot
- Tu, 02.03.2021, 11:13: The shipment has been loaded onto the delivery vehicle
- Tu, 02.03.2021, 12:24: The shipment has been successfully delivered
On the way back, we took a little detour and walked through the forest of the
- At 16:00, pole 834-A.
- At 16:03, pole 834-B (stone 12).
- At 16:17, pole 834-C (stone 13).
- At 16:33, pole 834-D (stone 14).
- At 16:41, pole 834-E (stone 15).
While biking home, I saw a sun pillar, which is light pillar of the sun. When the sun was setting below some clouds at
the horizon, I took the following
Conny and I continued our search for
border poles. We walked through an area in
Germany where all the roads are called Nork. We encountered the following
We did see pole 835B from a distance in the fields. From there we walked on
the right side of the spring Zoddebeek, which in Germany is called Zoddebach.
We got a little lost and had to cross the spring at a weir
- At 15:49, pole 834-F.
- At 15:53, pole 834-G.
- At 16:25, pole 835-A (stone 17).
- At 17:16, pole 835 (stone 16).
Since just less than a week, non-essential shops are allowed to open again in
the Netherlands for customers who have made an appointment in advance. About a
week ago, I made an appointment to visit the charity shop Het Goed between 16:00 and 16:30. At 16:23, I bought the
book 1001 Boeken die je gelezen moet hebben edited by Peter Boxall,
written in Dutch and published by Librero Nederland b.v. in January 2017,
ISBN:9789089988058, from for € 3.95 at the store. I also made some
donation to express my gratitude and to compenstate for their losses during the
lock-down. I used to visit this shop about twice a week and I might have spend
the donated amount in case they would have been open.
This evening, I saw a triangle with the letter R.D. in an atlas at the
location where we searched for the Dutch trigonometric point 340306. I tried
to find some more information about it on some geocaching sites and on one of
the sites, I found a link to an excel sheet with information about all Dutch trigonmetric points. To
my surprise, I found that point 340306 has been cancelled. On PDOK viewer it is now shown when the RDinfo, Punten dataset is selected.
Information about this can be found on RD-coördinaatpunten als open data (in Dutch) when entering the
number below 'Puntnummer ingeven'. It gives the following information about
the various points involved:
- Nr 11: Year 1987, X-RD 253223.6083, Y-RD 459890.5325,
52°07'06,59457" North, 6°49'17,00840" East,
description (extern) 'Steen R.D.',
(intern) '38.590 m N.A.P. (1986)'.
- Nr 12: Year 1902, X-RD 253223.6083, Y-RD 459890.5325,
52°07'06,59457" North, 6°49'17,00840" East,
description (intern) 'Tegel onder steen R.D. (1902)'.
- Nr 13: Year 1986, X-RD 253314.2021, Y-RD 459881.7972,
52°07'06,25403" North, 6°49'21,75993" East,
description (intern) 'Bronzen bout in de kop van grenssteen nr. 834.; 40.187 m N.A.P. (1986)'.
- Nr 14: Year 1986, X-RD 253222.3495, Y-RD 459856.5064,
52°07'05,49468" North, 6°49'16,90690" East,
description (intern) 'T.P.steen aan de rand van het bos; 24.8 m ten Z. van het bospad.'
drawing, I understand that the distance between Nr 13 and Nr 14 is 156.9,
and that 9.5 perpendicular from 66.0 from Nr 13 to Nr 14 is the location of
Nr 11 and Nr 12. The drawing seems to suggest that Nr 14 is at the border, but
the location is actually in Germany, which matches the description that talks
about 24.8 meter South of the forest path.
Conny and I walked continued our search for
border poles. This time we walked near the
Haarmühle, which is a watermill just over the border with Germany. The
current mill is from 1619. The previous watermill was from 1331. There is a
mentioning of the name Haremole from 1188, which suggests that there was
already some watermill in that periode. The current watermill was restored in
1988. Since 2000 is also used to produce electricity, We encountered the
following border poles:
- At 10:12, pole 835-C.
- At 10:17, pole 835-B (stone 18).
- At 10:28, pole 836-A.
- At 10:29, pole 836-B.
- At 11:06, pole 837-E (stone 21).
- At 11:11, pole 837-F (stone 21A).
- At 11:14, pole 837-G.
- At 11:20, pole 837-H.
- At 11:28, pole 837-J (stone 22).
- At 11:37, pole 838 (stone 23).
- At 11:50, pole 838-A.
- At 12:00, pole 838-B (stone 24).
- At 13:11, pole 837-C.
- At 13:13, pole 837-B.
- At 13:16, pole 837-A (stone 20).
- At 13:20, pole 837.
Game of Thrones: Season 8
This evening, we watched Games of Thrones (season 8). We watched the previous seasons in the
past months. often not more than watching three episodes per evening and
about five episodes per weekend. When we, after having seen four episodes,
discovered that there were only two left to finish the series, we decided to
watch the last two as well. I remembered that many people were disappointed
when watching the final episode when it was broadcasted. I also recall that it
was shown in movie theathers here in the Netherlands. I can now understand why
some people were disappointed. It felt a little as an epilogue after the first
third of the episode. But it does feel like in accordance with what George
Martin might have had in mind to finish this series.
Dell Latitude D630
This afternoon, when I prepared our Dell Latitude
D630 to be used by Andy, I accidently plugged
in the wrong power plug, one that has a slightly larger center plug. After
some time, Andy pointed out to me that the battery light was blinking. When I
plugged in the correct power plug, it kept on doing so. I concluded that I
must have destroyed the charging port. I tried to open it, which took some
effort, but I was not able to get to the charging port. Because Andy is the
only one who has been using it in the past years, I decided to leave it as this
and maybe dispose of it. I did take out the 2Gbyte memory module and the
Conny and I drove along ten of the cities
billboards that usually show information about events in the coming months, but
till the end of the month act as an outside exhibition, called
Passing By with 19 reproduction of art works of just as many graduates
from the AKI from 2020. These are the
graduates as we encountered them on our route:
Back at home, I made a map of the route we took.
- At 13:53, Inbar Damhuis
- At 13:53, Eva Oomen
- At 14:02, Bas Schippers
- At 14:02, Kaja Dunnewind
- At 14:13, Nikki Kirpestein
- At 14:19, Nienke van der Burg
- At 14:19, Sietske Feenstra
- At 14:30, Esmee van Zeeventer
- At 14:30, Lisa Maartense
- At 14:51, L3x_shemanski
- At 14:51, Matthijs Jeuring
- At 15:08, Elma Greven
- At 15:08, Maran Post
- At 15:21, Tessa Langeveld
- At 15,22, Shari Mona Cinzia
- At 15:36, Thijs Segers
- At 15:37, Nicky Goldsteen
- At 15:49, Gideon Eillert
- At 15:49, Lasity Last
It was a windy day with rain and sunshine quickly following each othere, a
typical rainbow day. We saw two rainbows at
Conny and I spend some time walking near
Losser, searching for
border poles. We ended up walking a part along
a walking path called Graafschapspad which was flooded at certain
locations probably because of the high water level in the Dinkel river.
We encountered the following border poles:
There are some poles between pole 4 and 5-I, but they are between a nature
reserve (on the Dutch side) and private property (on the German side). There
are also some poles between 6-I and pole 11 that are along farm fields. When
walking back, we looked if we could locate these from the path we walked. I
took some tele pictures from places where we thought to see a pole. At home,
I did discover a pole in one of the pictures. I think it is either from pole 7
or 7-I. At home, I spend a long time investigating all kinds of maps (from the
Dutch websites: topotijdreis,
PDOK viewer, and HISGIS, horigheid) because there has been some border changes after the
second war. An area of about one square kilometer was
annexed in 1949 and for the most of it returned in 1963 except from some
farm field on the east bank of the river. I studied some old maps and also
discovered something about four poles, numbered 8, 9, 10, and 11, that were
placed two by two on both sides of the river as shown on a map from 1832. In
the past centuries the river often changed it course and now is east of the
location where these poles where placed. I created a KML file (to be viewed in Google Earth)
with my findings so far, which I probably will update again. It seems that one
pole has survived. In the area an artwork with the name De landmeter
(the surveyor ) has been placed. We have not visited this.
- At 11:39, pole 4.
- At 12:25, pole 5-II, which is almost submerged.
- At 12:29, poles 5-III and 6.
- At 13:22, pole 11.
- At 13:30, unmarked border stone.
- At 13:32, unmarked border stone.
- At 14:25, pole 6-I.
- At 14:31, pole 5-I, which is almost submerged.
This afternoon, at 14:00 (CET), I gave the workshop A modern approach to parsing programs as part of the CyberSaturdays of TkkrLab. For some
unknown reason, the mircophone of my headset was not working, and I had to use
a MacBook of someone else. My intention of the workshop was that everyone, no
matter their level, would get something out of the workshop. But afterwards, I
felt that I had failed this objective. I realized that in the past weeks, I
spend a lot of time working on the materials and the programs, instead of thinking about the workshop
itself. I think that my previous experience would be enough to just improvise
during the workshop, but I am afraid I was blinded by my pride to realize that
giving a workshop online is a quite different. I think, I should have taken
some time at the start to see the attendees and ask them about their experience
level. I also think, I should have started with an example of parsing an
expression and evaluating its value and use this as a starting point to explain
everything that is needed to parse it. Something, like I start doing at 22:22 of the presentation.
Taking the normal priority rules used in numerical expression, I could have
explained the use of priorities and how you could use a formal grammar to
And then only explain something about the history of parsing and how I started
developing IParse and that I took a very different
approach from the traditional way of developing parsers. I remembered, for
example, that IParse cannot parse all Context-Free Grammars (CFG), but that this has never been a problem for all the
practical grammars that I have encountered in the past 20 years. Apparently,
grammars used for programming languages are more limited than the general class
of CFG, probably due to what can be easily comprehended by us humans.
This morning, I was looking through the book Grensgang: een historische reis langs de randen van Overijssel (in Dutch)
written by Jan ten Hove (starting from the back). It is about the history of
the borders of Overijssel described as a trip along the border. On page 149, I found a
reproduction of a drawing by Otto Koolmann about the 'Verzekeringsstenen',
which could be translated (from Dutch) to English as 'assurance stones'. They
are at a place where a turn of the border with Germany was established in the
middle of the river Dinkel.
To define it, on each side of the river two poles were placed, where the
crossing point of those poles defined the exact position of the turn in the
border. However, the river, as most rivers, was meandering, and over time some
of the stone poles, (mostly on the German side) were washed away. To overcome
this problem, four new stones were placed at a larger distance of the river as
kind of assurance. Hence the name of these poles. We realized that the two
unmarked stones we found last Thursday might have been
two of the four verzekeringsstenen. We also read some account of some unmarked
stones on the other side of the river. This afternoon, Conny and I decided to have a closer look and try to determine the
location of the stones with GPS. We encountered the following stones and
At home, I used the coordinates to locate the position of the orginal four
border poles (with the numbers 8, 9, 10, and 11 of the pre-1949 border) using
the drawing by Otto Koolmann. I tried to match these with the cadaster map of
1832 from the area, but failed to make an exact match. The article (in Dutch)
Verzekeringsstenen by Aafke de Wijk suggests that the two stones on the
former Dutch side of the river might be two of the original border stones. I
think that is not very likely. Conny send me a link to the article Loakgang langs de Markestenen en Rijksgrenzen van
de Marke Losser, which was published in Oet Dorp en Marke with some
more information about the part of the border we visited. In it we also read
that the location were we parked our car last Thursday has a history that goes
back to the fourteenth century and that just North of border pole there used to
be a neutral area where border disputes were resolved.
- At 13:17, unmarked stone on the former Dutch side
at approximately 52°17'00.5"N 7°01'30.6"E.
- At 13:40, unmarked stone on the former Germany side
at approximately 52;deg;17'01.0"N 7°01'40.2"E.
- At 13:42, unmarked stone on the former Germany side
at approximately 52°17'03.3"N 7°01'39.5"E.
- At 13:46, pole 11-II.
- At 13:52, pole 11-III.
- At 13:56, pole 12.
- At 14:25, unmarked stone on the former Dutch side
at approximately 52°17'01.7"N 7°01'30.4"E
about 15 to 20 meters to the North of the other.
Border changes around Losser
I continued working on a KML file (to be
viewed in Google Earth) about the border
changes just North of Losser. I spend a long time determining the position of
the border poles 8 to 11 using the available
data. The positions I have chosen, are inferred from cadaster data from now and
1832, do not perfectly match with the positions I calculated from the positions
of the assurance stones and the map by Otto Koolmann.
They are about seven meter off. My GPS measurements of the locations are
probably not very accurate. The possibility that the border poles have been
moved between the two dates, should not be excluded, because it is known that
the poles were washed away several times by the meandering river. I do not know
if it is possible to get more accurate GPS locations (without having to spend
hunderds of Euro's). I found the ArcGis viewer where you can get GPS coordinates on a recent
topographic map. It did show a dot at the location of one of the assurance
stones. The GPS locations where close to the one that I measured myself. I used
the viewer to adjust the GPS coordinates of some of the border stones along the
current border. The KML file contains the following folders:
Besides the folders there are also some border poles that were used during
periods before and after the annexation.
- Losserbrugge: Some border poles based on a map just North of border pole 6
where there was a neutral area.
- Koolmann: With the position of the assurances poles and the positions of
the border poles based on the map of Otto Koolmann around the start of the
- Before 1949: With border poles on the border before April 23.1949.
- 1949 - 1963: With (wooden) border poles for the border from April 23, 1949
till August 1, 21963.
- After 1963: With some border poles placed after August 1, 1963.
- From 1988: With some border poles that were only shown on a map after 1988.
Conny and I revisited Coevorden to look for
border poles we had missed on previous visits
after I created a GPX file with waypoints using the ArcGis viewer and downloaded this (through Google Drive) to OsmAnd on my Galaxy Tab 3 tablet.
The weather was a bit rainy for most of the time. We had brought some devices
to remove weeds and brambles. We encountered the following border poles:
We searched for about a quarter of an hour for pole 133-III, cutting away
weeds and brambles, but failed to locate it. To our horror, the area where
poles 145 to 146 stood is now a construction site with a large warehouse like
building surrounded by parking lots (still under construction). It seems the
poles have been removed. We also searched for poles 151-VI (D) and 152-I (N).
It looks like these two have disappeared.
- At 13:05, pole 133-I again.
- At 13:10, pole 133-II. Almost submerged.
- At 13:19, pole 134.
- At 13:25, pole 134-I again.
- At 13:30, pole 134-II again.
- At 13:35, pole 135 again.
- At 13:36, pole 135-I. (Plate says 135 with carved I.)
- At 13:39, pole 135-II.
- At 13:44, pole 135-III.
- At 13:45, pole 136.
- At 13:52, poles 137 and 137-I again.
- At 15:15, pole 147-I again.
- At 15:17, poles 147-II (N) and 147-II (D) again.
- At 15:21, pole 148 (D) again.
- At 15:22, pole 148 (N) laying in a ditch.
- At 16:25, pole 152-I (D). Almost submerged.
On February 5, 2019, I wrote about hexagon
numbers. Today, I discovered that the numbers I found, are sequence A229757 in the On-Line Encyclopedia of Integer Sequences. With the sequence, there
are references to two publications:
Reguläre Dreieckpflasterungkonvexer Polygone.and
Tiling Convex Polygons with Congruent Equilateral Triangles by Eike Hertel
and Christian Richter. The second paper is an extension of the first one with
respect to proofs. The numbers for pentagons the numbers are related to
the Idoneal numbers.
It is not known if there are more idoneal numbers than the one that are known,
but there are no more if generalized Riemann hypothesis is true. As a pentagon can often be
changed into a hexagon by removing, one would expect that both sequence match
with an offset of one. That is indeed the case for many numbers, but not all.
The first two flowers of our magnolia have opened
The temperature at Twenthe Airport went up to
24.4° Celsius, which breaks the previous record of 23.7° for the
temperature on this date in 2017. The predicted temperature according to the
prediction at the start of the day, was 21.8° Celsius.
This months interesting links
| February 2021
| April 2020