Håkon Robbestad Gylterud

This is my public diary.

2017 2018 2019 2020 2021
January January January January
February February February February
March March March March
April April April April
May May May
June June June
July July
August August
September September September
October October October
November November November November
December December December December

2021-05-12, Wednesday

Today was the the kindergarten surrogate 17th of may celebrations. Parents keept their distance, watching the children march around from outside the fence.

A COVID-19 perspective on 17th of May [Zoom in! 🔍]

After watching the little parade, I went for a walk in the sunny May weather. We took our usual route up to Montana, and stopped on a playground.

Spring flowers all around. [Zoom in! 🔍]

It has been a while since I got to do any photography, but since I had my camera with me I took some pictures on our way.

Self portrait. [Zoom in! 🔍]

2021-07-29, Thursday

Got my first COVID-19 vaccination dose today – Moderna.

2021-08-01, Sunday

Spent the weekend on Stord. Have been listeing to some new music lately.

Most of all I have been listening to the King Gizzard & The Wizard Lizard’s new album, called Butterfly 3000 – and it is such a blast! It’s a synthy album with lots of catchy tunes and vocal parts. Brilliant!

Their music vids are interesting too: Bye-bye Shanghai reminds me of the Gerald Scarfe’s animations for Pink Floyd, while in Catching Smoke they all have lost their eyebrows! And what’s with that sheet music?

The cover of Butterfly 3000 – are these dead butterflies, I wonder? [Zoom in! 🔍]

Also recently released (according to my standards) is Greta van Fleet’s album The Battle at Garden’s Gate. This album gives off such positive vibes: Listen to this!

The cover of The Battle at Garden’s Gate [Zoom in! 🔍]

Kamasi Washington’s song Fists of Fury from Heaven and Earth, has been on heavy rotation lately. It is such a powerful tune! The lyrics just striking:

I use hands
To help my fellow man
I use hands
To do just what I can
And when I’m faced
With unjust injury
Then I change my hands
To fists of fury!

People who know me will attest that I mostly listen to stuff from the seventies, but as the above indicates I have lately tried to keep my eyes open for new stuff. There is just so much music being made every year! And even the old stuff gets better, in the sense that remasters and high resolution versions are now avaiable. Did a comparison of different versions of Bohemian Rapsody here the other day, and the HD remastered version was so clear and just a bliss to listen to!

I have also been discovering new old stuff. Over summer I have been reading a (quite academic) book on psychedelic pop music: Psychedelic Popular Music – A history through musical topic theory by William Echard. One thing I learned from this book is that the music from Western movies had a big influence on early psychedelic pop. The book also has so many examples, which I have gone online to listen to while I read, and this has opened my ears to stuff like The 13th Floor Elevators and The Yardbirds. Perhaps the most trippy is I had too much to dream last night by The Electric Prunes.

I had too much to dream (last night)! [Zoom in! 🔍]

2021-09-09, Thursday

Home school and COVID-19 testing for my oldest this week. I got my second dose of Moderna tonight. Drop-in at Sentralbadet:

Enlarge the map.

I wonder how much I will notice the side effects tomorrow. I have a lecture and a lot of meetings.

2021-09-10, Friday

Side effects of my second Moderna dose kicked in after my lecture. Feeling nervous and unwell, so I plan to stay in bed the rest of the day while my immune system is updating. No meetings.

2021-09-11, Saturday

Woke up almost fine again. Immune system updated successfully ☺

2021-09-14, Tuesday

Got my modular synthesiser a new module called Surface by Qu-Bit.

Surface is a physical modelling sound source with eight models, ranging from plucky strings to percussive drums. So far, I have made pleasant ethereal string sounds – time-streached through Beads. But I also got some angry, distorted guitar sounds by switching Surface to its Dark mode and running it through the Black Hole DSP2’s more extreme effects.

The only drawback I see with this module is the lack of attenuators on the inputs.

My instrument – See it on ModularGrid or [Zoom in! 🔍]

2021-10-01, Friday

Busy at work these days. But tonight I had time to play on my synth again. Enjoying the Qu-Bit Surface quite alot. This time I was pushing it through the ADDAC T-network module – which I usually use as a “drum kit”, but this time did the job of a destructive filter. The result was a very rough guitar sound, which I ran through a delay (Beads in delay mode, actually!) to make the rythm more interesting.

One thing I struggle with at the moment is finding matching sounds. Before I started twiddling the Surface tonight, I had Plaits making the most wonderful spacy little sounds through a low pass filter delay. But what I ended up with from the Surface did not fit at all together with that. But each thing was awsome separately, so I guess I am happy ☺

2021-10-16, Saturday

Home alone. Kids and wife are visiting my parents in the weekend while I get some extra work done. While working I listen to music, and took a few breaks on my Eurorack synth.

My instrument – See it on ModularGrid or [Zoom in! 🔍]

Explored some more of the Qu-Bit Surface models, and discovered the joy of side-chaining when testing the kick drum model. Side-chaining the kick means that you lower the volume of other components when the kick drum hits. This let the kick cut through the mix, giving it a strong emphasis.

Side-chaining is often done by a compressor which follows the volume of the side-chained kick and correspondingly lowering the volume of its main input. In my Eurorack system I don’t have an envelope follower (yet? I am out of HPs, send help ☺), but I have the trigger signals for the kick available, so I can just trigger an additional envelope and use that to dampen the volume of the main.

2021-10-17, Sunday

In a spur of the moment I recorded some playing my new patch:

A bit repetitive, but it was fun to play.

2021-10-24, Sunday

Relentless rain this weekend. On Friday morning the rooftops around us were white, but the snow was mixed with rain already in the air and quickly melted. Today, I did not even venture outside. The youngest of our sons has been home with a cold all week, but seems fit for fight again tonight. Our oldest celebrated the UN day by drawing eighteen flags from all over the world.

Today is the UN day.

2021-10-28, Thursday

Held the department seminar today, on the topic “The univalent notion of equality”.

This was an introductory lecture about the propositions as types interpretation and univalence. [See the slides 🔍]

2021-11-01, Monday

Held the Bergen Type Theory seminar about Myott. A short demonstration of the program and a bit about the theory behind.

2021-11-11, Thursday

Roger Antonsen was in Bergen today to hold the department seminar. His talk was really inspiring – demonstrating lots of ways of visualising mathematics. After the talk there was a dinner at “Dr Wiesener” – a homely pub in Sandviken.

2021-11-16, Tuesday

Last week I recorded a new track on my synth.

This is a very Eurorack hipster kind of track. But I like it:

2021-12-03, Friday

Presented at the Bergen Interdisciplinary Research in Logic workshop (This is actually the program from last year, when the workshop was cancelled). It has been a nice day of logic related researchers in Bergen presenting their work to each other. Pleasantly surprised that there is this much logic going between Løvstakken and Fløyen.

The workshop programme. [Read the abstracts 🔍]

2021-12-10, Friday

My son’s school has closed early for Christmas, due to a COVID-19 outbreak. They of course call it “home school”, but all that means is that they got some homework with them, which takes him all of ten minutes to complete. The school closing was not entirely unexpected, but it doesn’t make Christmas preparations any easier. At work I am burried in exam corrections. Hoping to be done by the end of next week.

2021-12-22, Wednesday

Went to the movies today with my wife and saw “Verdens verste menneske”, which we really liked. We also finished Christmas shopping. This year more than any previous year I feel the absurdity of Christas presents for us adults. But, I did enjoy finding books to buy for my sister and her husband, Tony.

Verdens verste menneske.

2021-12-23, Thursday

Finally Christmas break! Going to Stord today, where my oldest is already waiting. He first went there for a few days when school just closed, then again on Sunday. Otherwise I would have no way to get all the exams corrected before Christmas.

Just before we left, I got new modules for my synth – a kind of reward to myself for completing all the exam corrections in time. Especially excited for the Belgrad filter by Xaoc devices and the Generate 3 oscillator from Joranalogue Design.

Generate 3 is an oscillator with phase modulation and through-zero frequency modulation

2021-12-31, Friday

New Year’s Eve again! This year, as last, we had Andreas over for Russian style new year celebration with Shuba and other goodies.

Looking back on this year, I am rather happy with how the first half turned out, especially nice to be on parental leave and spend time with my youngest. The autumn was very colored by the pandemic. My oldest started school, but they quickly had a week in quarantine. And my youngest kindergarten had a big outbreak in the beginning of December. Now we are hoping that Omicron will be less lethal and displace delta. If that happens we might just have to accept that the pandemic is going to run its course, and get on with our lives.

This is also a year in which I have spent a lot of time on modular synthesis. I got my Mother-32 a few years ago, but I started buying more modules this spring, and now I have 9U × 104HP of modular goodness.

2022-01-28, Friday

A childhood friend of mine from Stord disappeared after a car crash this week and we can only fear the worst. My thoughts go to his parents.

2022-01-29, Saturday

The winter weather in Bergen has been awful this year. No snow, just rain and wind. But that’s no excuse to sit inside when you have kids. So, both before and after lunch we were outside and played today in the cold winter rain.

Inside my synth is keeping me sane. I am discovering wave folding and through-zero FM – which suprsingly are not too different!

The basics of a kick drum is a sine wave through an exponential decay envelope. So, what I have done lately is to push the filter on the Erica Synths Pico Noise to self-resonance, since it has a built in exponential decay envelope with trigger input. But that sounds a bit tame on its own. So, what I have discovered is that I can put it through the wavefolder and drive of Captain Big-O, and get a more gritty sound. The result is something like this:

2022-02-13, Sunday

Our turn to test postive to COVID-19. So, for the next few days we will have to stay at home and weather the symptoms as best we can.

2022-02-24, Thursday

Putin’s army is invading Ukraine. Attacks on many cities started in the night. Reports of fighting at airports. We have known that hundreds of thousands of troops have been gathering at the border, but not everyone were convinced the attack would come.

Horrifying that war can still break out in Europe. Ukraine is not in NATO or EU, and so seem very on their own. A sad day for the Ukrainian and Russian people – who share so much culture.

2022-03-01, Tuesday

After a hard start of the term, and a round of COVID-19, we have a few days off. The kids are going to visit their grandparents on Stord, while me and my wife go to Solstrand.

The war in Ukraine weighs heavy in our minds. After the first few days, the western world is impressed with how strong the Ukrainian resistance has been. Steep sanctions have been put on Russia from the western countries, and thousands of protestors have been arrested in Russia.

2022-03-07, Monday

Another week, another virus. We seem to have caught a regular cold this time, with sore throats and cough.

2022-03-20, Sunday

Listening to Ghost’s new album IMPERA and preparing lectures. I think Ghost was one of Erik’s favorite bands, but this is actually the first the first time I have taken time to listen to them – and I quite like it!

Ghost’s new album

2022-04-03, Sunday

Spending the weekend at my parents place with the kids. This time we arrived in our own car. My parents are also building a cabin in the mountains, which I look forward to visiting some time.

2022-04-19, Tuesday

Our family just had our fifth round of illnesses so far this year (most of them coming from kindergarten). Apparently we have all been too hygienic during the pandemic and now that we have gone back to meeting other people every virus is going around.

During Easter I was a few days in Oslo. While there, I popped into the new Deichman Library. There was no time to do much but soak a bit in the atmosphere and snap a few photos.

Students working at Deichman. [Zoom in! 🔍]

2022-05-20, Friday

In Stockholm for a meeting in the EuroProofNet COST action’s 6th working group. Feels good to visit Kräftriket one last time before the math department there moves to new facilities across the road. Kräftriket is so beautiful in summer, and I have many fond memories from my time there. Even got to say hello again to Per Martin-Löf who is still active in attending seminars!

Group photo from the workshop

2022-06-05, Sunday

As one might, I have been watching the fourth season of Stranger Things, and in the fourth episode there was a moment – a little joke – which I derived great pleasure from. Mostly because I imagine not a whole lot of people would notice or have the prerequisite knowledge of English garden landscaping to laugh at it.

So, for your benefit, so that you can also enjoy this little moment of the episode, let me introduce the “ha-ha”:

A comparison between ha-ha and regular walls. (842U / Wikipedia / Gnu Free Documentation Licence)

As you can see, a ha-ha is kind of a wall, but the ground on one side is as hight as the wall. A ha-ha is useful when you want a wall, but don’t want to ruin the view from the inside. Here is a real world example:

Hopetoun House ha-ha. (Andrew Shiva / Wikipedia / CC BY-SA 4.0)

And here is one from one of my MineCraft castles:

A ha-ha keeps the monsters out of my MineCraft home

Back to Stranger Things. In episode four of the forth season, Nancy and Robin visit an asylum in an attempt to get one of the inmates there to talk about how a demon killed his family fifty years ago. They pretend to be psychology students, and while they are given a tour of the place, we briefly see what looks like a ha-ha. So, like anyone with an interest in obscure walls, I nodded to myself: “Ah, see now there is a nice ha-ha, if ever I saw one.”

Nancy and Robin get to talk with the fellow, but in the end their cover is blown, and they have to make a run for it. And as they do, we get a great shot showing how ha-has are almost invisible from the top:

Do you see that there is a wall here?

For a moment I worried that they would not notice the drop and fall. Indeed, one can imagine the origin of the term “ha-ha” to be “Ha,ha! You fell and broke your leg!”. But they actually jumped down rather gracefully:

Down the ha-ha!

And then, the creators had a brilliant idea, as a tip of the hat to anyone enjoying the landscaping at the asylum, one of the inmates exclaims “Ha ha ha ha ha ha!”.

“Ha ha ha ha ha ha!”

Here is the whole sequence:

2022-07-15, Friday


This week we returned from a vacation trip to Stockholm. The SAS pilots are on strike, because SAS broke the contract they made to rehire pilots after the COVID-19 pandemic crisis was over. Our plane to Stockholm was scheduled 13:25, and the strike was due to start 12:00. But it turned out, that while it is a SAS route, SAS was not actually flying the plane – CityJet was. So, we got both there an back again despite the strike.

Synthy times

Today, I spent some quality time with my synth. The rack was reorganised earlier in the week and I tidied the desk it stands on. I still struggle a bit with doing several takes on multitrack recordings, but some progress is being made: A new clock divider now makes it possible to use the KeyStep 36 as a clock source. The KeyStep also starts the recording, so with a bit of practise I should be able to sync the different takes up directly.

The track I recorded today was initially by the new layout of the modules, where a choice of voices (oscillators + filter/wavefolder + envelope generator + vca) have been constructed. Aaaand, Rings is playing a baseline ☺

Looking through the memory card, I found a few other tracks which were recorded, but not edited. So, I got those done as well. I actually do very little editing after recording. All effects and mixing is done at the synth. All I really do is to even the levels a bit of different parts of the track.

Since there was a few weeks since I recorded these, I cannot really remember what inspired them. But you can listen to them here:

Actually, listening back to these, I remember that “Toy box” is in fact just the Qu-bit surface, cycling through different modes.

2022-08-10, Thursday

Back at work for almost two weeks already. Mostly preparing for teaching functional programming.

Generative art

I have discovered MidJourney, one of these machine learning image generation tools where you write a prompt and it generates an image. It is really fun! Of course it has its strengths and weaknesses. But, more than with other “AI things”, I feel like this has real, human value. Also, the community around MidJourney is exciting.

A mindflayer, adapted to a D&D champaign set in a fantasy dessert world. [Zoom in 🔍]

Generative art is nothing new. The core of generative art is that you write an algorithm which generates the art, rather than “performing it” yourself. Often you incorporate some source of randomness into the process, so that you can get a number of variations on the same theme. The algorithm can also take some user input, which affects the result in some way.

In the case where you wrote the algorithm, the result is clearly art you have made. But even if you are merely using someone else’s algorithm, you might claim that the result is art you have made, if one or a combination of the follow two cases hold:

  1. Your input to the algorithm enabled your artistic expression.
  2. Your selection of this output from many randomly generated outputs enabled your artistic expression.

Musical example

Here is a simple example from music of the second case: In modular synthesis you make music by connecting modules together to form a synthesiser.

Often the notes played is determined by a sequencer module, instead of using a key board. Some sequencers allow you to program in a sequence of notes played manually, but there is a sequencer called “Turing Machine”1 which generates random sequences of notes.

The crucial thing about the Turing Machine is that it will play random notes until you lock it. Once the sequence is locked it will keep playing the last generated sequence until you unlock it. So, to produce a cool bassline for your track, you connect the turing machine to the bass modules, and listen to its random playing until you find something you like. Then you lock it in, and that’s it! Clearly it is your bassline because you chose it among the many different ones generated by the Turing Machine.

Here is a track where Mutable Instruments’ Marbles, another module like the Turing Machine2, is used to decide the melody played:

Foot Stomp

The theme you hear repeat a few times throghout track was chosen by just letting Marbles “roll the dice” until a catchy melody came out. Then I was free to focus on other parts, such was how to make the most bad-ass distorted sound to play that melody with.

BTW, that distorted sound is a harmonic oscillator (sum of related sine waves) modulating a through-zero FM oscillator. Controlling the distribution of sines gives absolutely interesting shifts in timbre!

DALL-E, MidJourney and others

Currently there are several competing prompted image generators. But the idea is that you give a short prompt such as “The invention of pizza by god, italian renaissance painting”, and the program spits out:

A critical moment in time, forever captured by this renaissance painting. [Zoom in 🔍]

In MidJourney the output is actually four images, and then you can iterate, making variations on each of them. This means that both the first and the second point above apply. The user provides both input to the algorithm, and selects from a supply of randomly generated output.

In both ways this enables the user to express themselves artistically. And this is the value I see in this: it enables more people to express themselves creatively using computer graphics. For instance, I will use MidJourney when creating concept art for my D&D sessions. The dessert mindflayer above is way better drawn that I would have been able to if I sat down in Krita or Blender.

Now, I don’t think MidJourney or DALL-E are any threat to actually skilled artists. A human artist actually understand what they are drawing, and can be relied upon in a completely different way. The pictures generated by MidJourney usually have very recognizable artifacts. And most importantly, the control you have when generating the picture is very tenous. You might have a perfect idea in your head, but the algorithm is not a mind reader, so the picture coming out is usually completely different. Sometimes that’s OK, and a cool feature. But for most of the kind of work you pay an artist for, it would be completely uselsess.

Also, artists often produce 3D models, which can be redered in many different settings and reposed. This has very high utility compared to the lump of pixes from MidJourney.

2022-09-30, Friday

Went bouldering after work with a group of coworkers. Its been a busy week, so it was good to just go do something physical. Climbing is a good way to exercise because it is just fun enough that you don’t notice that you are exercising. Each bouldering route is like a puzzle. Of course there is skill and physical form involved, but your thinking-brain is also involved. You need to figure out how to position your various limbs and move them in order for the route to be possible

«Climber», medium: MidJourney [Zoom in 🔍]

I am starting to get the hang of MidJourney now. And it is exciting! I like discovering what my prompts turn into. I don’t know anything about Brownsville, but I like the result which the word “Brownsville” prompted below!

«Dancing on the streets of Brownsville», medium: MidJourney [Zoom in 🔍]

2022-10-30, Sunday

Starting to see the end of the term approaching. Less than a month until my students have their final exam. For me “to see a date approaching” is quite literal. I see dates very clearly in my mind. They are distributed counter-clockwise on a roundish landscape which represents the year. As the year progresses my vantage point in this landscape moves so that I always see things from today’s date. Thus, the coming dates are approaching. There is also a kind of covering-space effect where the actual dates over many years cover the same landscape. In a path-lifting kind of way, I can see forward into the future, say next march, or backwards to the past, say to the previous march.

Next week we have a conference, Nordic Workshop on Programming Theory, which I am on the organisation committee3 for.

2022-11-11, Friday

Had an evening by myself. Spent most of it deep into my synth, exploring sounds and melodies. At some point I felt like I was having a party:

The sound is sub par since I was just recording it through my iPhone 7. And I made no recordings, but sometimes the point is just to play for my own enjoyment.

2022-12-23, Friday

Lille-julaften (“Little Christmas Eve”) here in Norway. As usual I am visiting my parents over the holiday, along with the rest of the family. This year’s new arrival, my sister’s daugther, is getting to know her cousins. In the evening we played the Dune boardgame, which is so much fun! Especially the battles are nerve-wrecking!

The spice must flow on Arrakis! But so too must the caffeinated drinks, keeping us sharp in intrigues that last into the wee hours. [Zoom in 🔍]

2023-01-02, Monday

Today our long awaited bathroom renovation starts. In a few days time we will have to do our business out on the balcony in a Porta Potty. At least we will have a view towards Ulriken as we take a shit.

2023-01-20, Friday

Today was the first lecture of my new course, INF221: Advanced Functional Programming. The little room which had been assigned to us was packed, but hopefully we will get a bigger room.

2023-01-25, Wednesday

So, tonight I found myself trying in vain to start the car, with the trunk full of shit. Literally, shit. I was on my way to empty the aforementioned Porta Potty and aparently the battery was flat.

Luckly the place to empty is just a 15 minute stroll from here! [Zoom in 🔍]

  1. No relation to the mathematical model of computation, except for the name.↩︎

  2. Marbles has the advantage of being able to do non-destructive variations, where you radomize the notes for a time then return to the previously locked tune.↩︎

  3. I love the amount of double letters in the word “committee”.↩︎

Expecting a comment section? Feel free to e-mail me your comments, or otherwise contact me to discuss the content of this site. See my contact info. You can also write your opinion on your own website, and link back here! ☺