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Mattias Petter Johansson (MPJ)

@mpj.fff.dev
253 followers 474 following 92 posts

Data Engineer 💛 Creator of the YouTube show Fun Fun Function, writes weekly data development chronicle: funfun.email 🦁Previously @ Spotify & parity.io

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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 04/05/2026
A Return to Fun funfun.email/p/return-to-...
I disappeared off the face of the earth, no notice, no goodbye. I was in the middle of weekly chronicles, a series on D3.js - and suddenly I was just gone. An explanation and apology is in order.
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Reposted by Mattias Petter Johansson (MPJ)
Oregon 🕎🎲 @oregonthedm.bsky.social · 09/04/2025
Biggest commitment to a 3 second joke I've ever seen
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 31/05/2025
I am reading Daniel Levintins excellent book ”The Organized Mind” and this part perfectly explains why I sometimes get stuck in multi-hour obsessive TypeScript rabbit holes to create the perfectly (unnecessary) typed expression for a problem.
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 27/05/2025
I love this format with @bashbunni.dev and I hereby promise publicly to try doing this. Also I so love the aesthetics and idea @charm.sh, makes me feel super great for some reason www.youtube.com/watch?v=Qpz0...
youtube.com
code with me for 1 hour (cozy, soft typing)
YouTube video by bashbunni
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 26/05/2025
💛 d3.interpolate (Number) | Dirty D3 - Episode 4 📼 Full video: youtu.be/6Vn1TWyOsYo #dataviz #d3js #fffn
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 23/05/2025
hmm should I make a Rough Regex course after my Dirty D3 series ends (in 2054)
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 23/05/2025
💛🌻🎉 #dataviz
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 22/05/2025
God I love force directed graphs
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 21/05/2025
💛It’s seldom one gets shoutouts for commercial partnerships, but @augmentcode.com really is that good - it’s really an incredible thing that a platform targeting large legacy codebases is free for OSS thx @adrienjoly.com
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 19/05/2025
New episode! 📽️💛 What is interpolation, really? | Dirty D3 - Episode 3 youtu.be/LOaqG--VWas #dataviz #d3js
youtu.be
What is interpolation, really? | Dirty D3 - Episode 3 (and "default interpolator"?)
YouTube video by Fun Fun Function
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Reposted by Mattias Petter Johansson (MPJ)
Dominikus @do.minik.us · 19/05/2025
I'm obsessed with this: Mystical, a visual representation of PostScript as magical symbols. What if software departments were catacombs of hooded figures scratching arcane circles into the dirt github.com/denismm/myst... (via @piterpasma.nl)
screenshot from the Mystical project. a visual representation of a PostScript file as several magical circles.
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 15/05/2025
I love love love this example, really visceral way of unstanding variance
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 15/05/2025
Great thread on dataviz animation ❤️
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Reposted by Mattias Petter Johansson (MPJ)
Тsфdiиg @tsoding.bsky.social · 02/05/2025
Humanity may never be able to find a counter-example to Collatz conjecture if this package gets removed from npm.
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 11/03/2025
Was sent this golden thing from 3 months ago written by @peck.phd
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 11/03/2025
mundus sine caesaribus
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 11/03/2025
Are you sure you want to hide the ads in your editor
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Reposted by Mattias Petter Johansson (MPJ)
Micah G. Allen @micahgallen.com · 10/12/2024
We often mind-wander about our past, present, & future. What happens when our minds drift towards our bodies? In a new fMRI study (n ~ 500), @leahbanellis.bsky.social + team discovers unique neural, affective, & physiological correlates of "body-wandering" at rest. www.biorxiv.org/content/10.1...
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Dr Lucy Foulkes @lucyfoulkes.bsky.social · 01/02/2025
Me in the WSJ today, arguing that the relationship between social media and mental health is not clear cut, and bans for teenagers aren't the answer. (NB I did not pick this title, I would have gone for something kinder. I understand why people are worried.) 1/ www.wsj.com/health/welln...
wsj.com
Essay | Stop Panicking Over Teens and Social Media
Modern life is digital. Adults need to help young people navigate the costs and benefits, not launch bans and hope for the best.
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Reposted by Mattias Petter Johansson (MPJ)
Luca Kolibius @lucakolibius.bsky.social · 05/03/2025
New manuscript published! ✍️👀 Concept neurons evolve from index neurons through overlapping memories. Check it out here: www.cell.com/trends/cogni... 1/15
cell.com
On the origin of memory neurons in the human hippocampus
The hippocampus is essential for episodic memory, yet its coding mechanism remains debated. In humans, two main theories have been proposed: one suggests that concept neurons represent specific elemen...
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Reposted by Mattias Petter Johansson (MPJ)
Camilla Nord @camillanord.bsky.social · 06/01/2025
Can what you eat change your mind? 🍎 My first piece in @theguardian.com on why we like what we like, and the role the gut might play in mental health. Hint: it’s probably not all about the microbiome.
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 06/03/2025
I find it so lovely that @augmentcode.com uses the separate domain name hkjl.ai for their @neovim.io integration 💛💛💛 much poise #neovim
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 06/03/2025
This beautiful video by Kurtzgesagt voiced by @johngreensbluesky.bsky.social captures well why I like following the Green brothers. LFG in an orderly fashion. www.youtube.com/watch?v=GFLb...
youtube.com
This Disease is Deadlier Than The Plague
YouTube video by Kurzgesagt – In a Nutshell
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 28/02/2025
but the bitcoin can be hacked at any time
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arxdraconis.bsky.social @arxdraconis.bsky.social · 24/02/2025
If you're curious about coding-assisted platforms (but tired of the hype and unfulfilled promises), have a look at this video about Augment Code. Maybe, just maybe, this is for you :) #aifordevs #aicoding youtu.be/LEOSWYlQyVw?...
youtu.be
From Physics to AI: Building a 200ms Coding Assistant | ft. Guy Gur-Ari, co-founder of Augment Code
YouTube video by Fun Fun Function
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 25/02/2025
How many % of the currently experienced value of large language models come from the fact that they ingest in a way that a traditional search engines would have been sued and blocked to oblivion if they did? And how expensive would they be if they paid fairly for the privilege?
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Reposted by Mattias Petter Johansson (MPJ)
Maarten Lambrechts @maartenzam.bsky.social · 25/02/2025
If you're into D3 or Observable, there is no doubt you ran into Fil at some point. I learned a ton from him, and this interview only adds to that
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 24/02/2025
I'm super duper proud to officially announce the FFF partnership with @augmentcode.com, the developer AI that I've been using as my primary for the last few months. Go give it a whirl using fff.dev/augment and let me know what you think!
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 24/02/2025
good monday morning #dataviz bluesky, I just dropped a new Fun Fun Function video: youtu.be/aAP3m0PyGrY

 'Line Plots are Plot Lines' 
 (a data visualization spoken word 
cover of funfun.email issue #12)
youtu.be
Line Plots are Plot Lines | A data visualization spoken word cover of funfun.email #12)
YouTube video by Fun Fun Function
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Reposted by Mattias Petter Johansson (MPJ)
Saloni @scientificdiscovery.dev · 24/02/2025
New article by me! It's a common mistake to think the TFR is a prediction of the average number of children women will have over their lifetimes. But it's not. The TFR can decline even when the eventual number of children per woman stays constant or even increases; the opposite can happen too. 🧵
A line graph compares two measures of fertility rates in Sweden over time: the total fertility rate and the completed cohort fertility rate.

The total fertility rate is depicted using a red line, which shows a downward trend starting around the early 1900s, with fluctuations and a gradual decline to about 1.5 in 2022. 

The completed cohort fertility rate is illustrated with a blue line, with the time axis showing the women's birth year. It shows an initial decline followed by a stable fertility rate.

A note at the bottom states that the completed cohort fertility rate has been shifted by 30 years to align with the respective birth years of women. The data source is the Human Fertility Database (2024) and the chart is published by Our World in Data.
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 22/02/2025
This wonderful man, @rshean.bsky.social, has written what Shakespeare would have, had he been working with Excel at scale* *= “scale”
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 21/02/2025
This was sort of foreshadowing youtu.be/ohDB5gbtaEQ?...
youtu.be
Argument - Monty Python
YouTube video by unmusedtails
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 20/02/2025
Sleep well
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 20/02/2025
Can you please explain #PowerBI to me? Wrong answers only.
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 19/02/2025
Very exhaustive test of Claude interpreting graph, fun to read!
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 16/02/2025
I like how well highlighted this was:
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 11/02/2025
So it is trained on your uncle on Facebook?
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 10/02/2025
I mean yes
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 10/02/2025
Just because you can, you should
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 10/02/2025
This was much news to me. Lots of interesting aspects with this article, but the detail that concept cells fire only after a 300 ms delay, for some reason, stuck out for me.
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Reposted by Mattias Petter Johansson (MPJ)
Ansgar Wolsing @ansgarw.bsky.social · 09/02/2025
It's that time of the year again. #SuperBowl 📊
A line chart titled "XIX, XLIX, LVIII!?!?" that shows the search interest for Super Bowl and "Roman numerals" on Google Search. Searches for Roman numerals peaks when Super Bowl searches peak, too.
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Reposted by Mattias Petter Johansson (MPJ)
Zack Labe @zacklabe.com · 08/02/2025
Saturday ice update - #Arctic sea ice extent is currently the *lowest* on record (JAXA data) • about 790,000 km² below the 2010s mean • about 1,450,000 km² below the 2000s mean • about 2,040,000 km² below the 1990s mean • about 2,430,000 km² below the 1980s mean Plots: zacklabe.com/arctic-sea-i...
Line graph time series of 2025's daily Arctic sea ice extent compared to decadal averages from the 1980s to the 2010s. The decadal averages are shown with different colored lines with purple for the 1980s, blue for the 1990s, green for the 2000s, and white for the 2010s. Thin white lines are also shown for each year from 2000 to 2024. 2025 is shown with a thick gold line. There is a long-term decreasing trend in ice extent for every day of the year shown on this graph between January and April by looking at the decadal average line positions.
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 08/02/2025
Binary slug
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 05/02/2025
Generally not posting political stuff but I found this opinion piece by @ezrakleinbot.bsky.social to be an interesting and calming take, and elucidating on what is going on in the media space. www.youtube.com/watch?v=K8QL...
youtube.com
Don't Believe Him | The Ezra Klein Show
YouTube video by The Ezra Klein Show
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 04/02/2025
Really looking forward to listening to this new investigative pod series by @suelinwong.bsky.social. I was made aware of this fascinating (and unnerving) phenomena through @pjvogt.bsky.social on the episode pjvogt.substack.com/p/whos-behin... and this seems like a much bigger deep dive.
bsky.app
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 02/02/2025
This was incredibly interesting, look at the video first and inspect your own response before reading further into the article, that makes the article a lot more interesting. www.effaff.com/the-data-sto...
effaff.com
The (data) stories we tell ourselves
Can geometric shapes be a**holes? What can Heider and Simmel's moving shapes tell us about interpreting visualizations?
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David Higham @oldtrotter.bsky.social · 31/01/2025
Astonishing article in today’s FT on the private parking industry. Of course, private equity is involved.
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Edward Harrison @edwardnh.bsky.social · 31/01/2025
On Nvidia, this chart from Deutsche Bank shows the earnings expectations baked into the company's stock price. I see it as completely unrealistic and a recipe for disaster tbh. Anyone who doesn't understand that AI is a mania needs to look at charts like this
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Reposted by Mattias Petter Johansson (MPJ)
Alex Selby-Boothroyd @alexselbyb.bsky.social · 31/01/2025
Bitcoin price tracker but only using headlines about the landfill hard drive
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Mattias Petter Johansson (MPJ) @mpj.fff.dev · 29/01/2025
American company Napster complains that their content is being made available in another competitive product without their consent www.ft.com/content/a0df...
ft.com
OpenAI says it has evidence China’s DeepSeek used its model to train competitor
White House AI tsar David Sacks raises possibility of alleged intellectual property theft
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