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Diary, June 2019



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Sunday, June 2, 2019

First hot day

Today, the temperature reached more than 30°C in the Netherlands. In De Bilt it reached 30.4°C, which is the highest temperature ever measured on this day of the year, and at Airport Twente it reached 30.9°C, which might as well also be the highest temperature ever measured at that location.


Saturday, June 8, 2019

Book

At 16:54, I bought the book Kunst werkt | Art works with an introduction by Renilde Hannacher-van den Brande, in Dutch and translated to English, published by Peter Stuyvesant Stichting in 1992 from charity shop Het Goed for € 2.50.



Sunday, June 9, 2019

Outdoor art

I first went to Kunst in het Volkspark (Art in the people's park). I found the following things interesting:

Next, I went to KunstenLandschap. At Tetem art space, I met with Willemijn Calis, who was there to show the augmented reality project she had been working on. I left my coat at Tetem, because it had got too warm outside for wearing a coat. I found the following artist worth mentioning (in the order I saw their works):

At location number 25, the farm "de Vèger", I found a copy of the book Stilte, ruimte, duisternis: Verkenning in de natuur (Silence, space, darkness: Exploration in nature) by Kester Freriks. I noted it, because I had just seen an art work with three wooden boxes with the words silence, space and darkness on them. Then someone told me that the book had served as the theme for this year. Somewhere along the route, I took a picture of a wild orchid and a picture of the sky.

Hollow chestnut

When I came home, I kicked against a hollow chestnut, while walking in the garden. It was the first chestnut that I found last year and placed in a pot. It started to grow and I noticed that the chestnut had become hollow. I do wonder how the hollow chestnut ended up on the path and suspect that some animal was involved.


Friday, June 14, 2019

Powers continued

Yesterday evening, I had a look at how the expressions of the powers of (a2 + b2) are related to each other and I arrived at this figure:

    1
   - +
  2   1
   \ + -
    1   2
   - + - +
  2   1   3
   \ + - + -
    1   2   3
   - + - + - +
  2   1   3   4
   \ + - + - + -
    1   2   3   4
   - + - + - + - +
  2   1   3   4   5
   \ + - + - + - + -
    1   2   3   4   5
The numbers in each line, stand for the equations and the '+' and the '-' symbols stand for the variant of the Brahmagupta-Fibonacci identity that has been choosen. The '\' is used when both '+' and '-' return the same result. This happens when one of the squares is zero. If seems that twice taking the same variant, leads to the same result. Lets see if this is generally the case:

(r2 + s2)(a2 + b2) = (rb + sa)2 + (ra - sb)2
((rb + sa)2 + (ra - sb)2)(a2 + b2) = ((rb + sa)b + (ra - sb)a)2 + ((rb + sa)a - (ra - sb)b)2 = (rb2 + sab + ra2 - sab)2 + (rab + sa2 - rab + sb2)2 = (r(a2 + b2))2 + (s(a2+ b2))2

(r2 + s2)(a2 + b2) = (rb - sa)2 + (ra + sb)2
((rb - sa)2 + (ra + sb)2)(a2 + b2) = ((rb - sa)b - (ra + sb)a)2 + ((rb - sa)a + (ra + sb)b)2 = (rb2 - sab - ra2 - sba)2 + (rab - sa2 + rab + sb2)2 = (rb2 - 2sab - ra2)2 + (sb2 + 2rab - sa2)2

Now, it seems that the results are not the same.

Sonic DIY

I the evening, I went to the second edition of Sonic DIY at Sickhouse in Enschede. First Patrick Jonkman gave a presentation about the history of electronic instruments. This was followed by a live performance by Dennis van Tilburg (on SoundCloud). Nicolas from soundforce told something about the Eurorack modules he is developing. It was mostly about a DCO (digital voltage controlled oscilator). After a short break, there were some five minute jam sessions with pairs of people. The jam was hosted by Gijs van Ouwerkerk with Ingmar Kops, Gregor Beyerle, Nicolas Toussaint, and Jasper Schütz. I listened to the first jam, but left the room when it became a little too hot for my tasted. I joined the Live Hex workshop held by Ole Nieling, which was about building a simple oscilator with the CD40106BE, also known as the Hex Schmitt Trigger (with inverter) IC. I build the basic circuit with a LDR and 10nF capacitor. I went on to experiment a little and put two oscilators in series using another 10nF capacitor. There were three more performances:


Monday, June 17, 2019

Puzzles by Annabel

In the past months, Annabel developed a set of eight fractal jigsaw puzzles. Today, she launched her website where they can be ordered separately or combined.


This months interesting links


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