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Start all of your commands with a comma

https://rhodesmill.org/brandon/2009/commands-with-comma/
143•theblazehen•2d ago•42 comments

OpenCiv3: Open-source, cross-platform reimagining of Civilization III

https://openciv3.org/
668•klaussilveira•14h ago•202 comments

The Waymo World Model

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949•xnx•19h ago•551 comments

How we made geo joins 400× faster with H3 indexes

https://floedb.ai/blog/how-we-made-geo-joins-400-faster-with-h3-indexes
122•matheusalmeida•2d ago•33 comments

Unseen Footage of Atari Battlezone Arcade Cabinet Production

https://arcadeblogger.com/2026/02/02/unseen-footage-of-atari-battlezone-cabinet-production/
53•videotopia•4d ago•2 comments

Jeffrey Snover: "Welcome to the Room"

https://www.jsnover.com/blog/2026/02/01/welcome-to-the-room/
17•kaonwarb•3d ago•19 comments

Show HN: Look Ma, No Linux: Shell, App Installer, Vi, Cc on ESP32-S3 / BreezyBox

https://github.com/valdanylchuk/breezydemo
229•isitcontent•14h ago•25 comments

Vocal Guide – belt sing without killing yourself

https://jesperordrup.github.io/vocal-guide/
28•jesperordrup•4h ago•16 comments

Monty: A minimal, secure Python interpreter written in Rust for use by AI

https://github.com/pydantic/monty
223•dmpetrov•14h ago•117 comments

Show HN: I spent 4 years building a UI design tool with only the features I use

https://vecti.com
330•vecti•16h ago•143 comments

Hackers (1995) Animated Experience

https://hackers-1995.vercel.app/
494•todsacerdoti•22h ago•243 comments

Sheldon Brown's Bicycle Technical Info

https://www.sheldonbrown.com/
381•ostacke•20h ago•95 comments

Microsoft open-sources LiteBox, a security-focused library OS

https://github.com/microsoft/litebox
359•aktau•20h ago•181 comments

Show HN: If you lose your memory, how to regain access to your computer?

https://eljojo.github.io/rememory/
288•eljojo•17h ago•169 comments

An Update on Heroku

https://www.heroku.com/blog/an-update-on-heroku/
412•lstoll•20h ago•278 comments

PC Floppy Copy Protection: Vault Prolok

https://martypc.blogspot.com/2024/09/pc-floppy-copy-protection-vault-prolok.html
63•kmm•5d ago•6 comments

Was Benoit Mandelbrot a hedgehog or a fox?

https://arxiv.org/abs/2602.01122
19•bikenaga•3d ago•4 comments

Dark Alley Mathematics

https://blog.szczepan.org/blog/three-points/
90•quibono•4d ago•21 comments

How to effectively write quality code with AI

https://heidenstedt.org/posts/2026/how-to-effectively-write-quality-code-with-ai/
256•i5heu•17h ago•196 comments

Delimited Continuations vs. Lwt for Threads

https://mirageos.org/blog/delimcc-vs-lwt
32•romes•4d ago•3 comments

What Is Ruliology?

https://writings.stephenwolfram.com/2026/01/what-is-ruliology/
44•helloplanets•4d ago•42 comments

Where did all the starships go?

https://www.datawrapper.de/blog/science-fiction-decline
12•speckx•3d ago•5 comments

Introducing the Developer Knowledge API and MCP Server

https://developers.googleblog.com/introducing-the-developer-knowledge-api-and-mcp-server/
59•gfortaine•12h ago•25 comments

Female Asian Elephant Calf Born at the Smithsonian National Zoo

https://www.si.edu/newsdesk/releases/female-asian-elephant-calf-born-smithsonians-national-zoo-an...
33•gmays•9h ago•12 comments

I now assume that all ads on Apple news are scams

https://kirkville.com/i-now-assume-that-all-ads-on-apple-news-are-scams/
1066•cdrnsf•23h ago•446 comments

I spent 5 years in DevOps – Solutions engineering gave me what I was missing

https://infisical.com/blog/devops-to-solutions-engineering
150•vmatsiiako•19h ago•67 comments

Understanding Neural Network, Visually

https://visualrambling.space/neural-network/
288•surprisetalk•3d ago•43 comments

Why I Joined OpenAI

https://www.brendangregg.com/blog/2026-02-07/why-i-joined-openai.html
149•SerCe•10h ago•138 comments

Learning from context is harder than we thought

https://hy.tencent.com/research/100025?langVersion=en
183•limoce•3d ago•98 comments

Show HN: R3forth, a ColorForth-inspired language with a tiny VM

https://github.com/phreda4/r3
73•phreda4•13h ago•14 comments
Open in hackernews

Show HN: An interactive demo of QR codes' error correction

https://qris.cool
109•Xiione•9mo ago
Hi HN! This is a hobby project of mine that recently landed me my first interview and helped me get my first internship offers.

Draw on a QR code, and the health bars will accurately display how close the QR code is to being unscannable. How few errors does it take to break a QR code? How many errors can a QR code handle? Counters at the bottom track your record minimum and maximum damage. (Can you figure out how to break a QR code with 0.0% damage to the actual data region?)

Also, click on the magnifying glass button to toggle between "draw mode" and "inspect mode". I encourage you to use your phone's camera to scan the code as you draw and undo/redo to verify that the code really does break when the app says it does.

I wrote the underlying decoder in C++, and it's compiled to WebAssembly for the website.

I hope you find it interesting.

Comments

flysand7•9mo ago
It's surprising how much data you need to corrupt while still being able to read the QR code, that's what I'd take out from this. The demo is interesting in that respect, but I do think it's somewhat incomplete.

It seems to be missing some explanations regarding how the code is structured and how it performs error correction. I feel like there's little point in interacting with a system you don't understand or not trying to understand. And I also think there are cool ways to make those things interactive as well. Pick an image, then explain what the little squares in the corners are for and provide little interactivity to see how they affect the decoding. Then move on to the error correction. This step-by-step style of interactivity may be better, I'd think about that.

As for what is there, the first thing I don't like here is icons. The four icons in the lower-right corner (result data, format info, ..) are hard to distinguish, and are hard to correlate with the "history" tab. I'd probably either make them slightly different color, or actually simplifying these icons further might be a better option, just because they're so small.

But yeah it is pretty hard to tell what I'm interacting with, unfortunately. I don't know pretty much nothing about QR codes, and I don't know what the different kinds of errors are, what "EC" stands for etc.

UI should probably be rethought as well, because before I was writing the comment I had no idea I could switch a brush. Hell, I had no idea I was changing colors (the cursor covered half the space of the pixels, so I couldn't tell)

The idea's cool though, good work

Xiione•9mo ago
Thank you so much for the honest feedback. One of the reasons I tried to not get into the math details is because the preliminaries would be somewhat lengthy, some people would not be familiar with what a finite field is so explaining even that succinctly would be its own challenge for me. But for those that the concepts are within reach for (like the folks here on HN), you are right that I ought to make some effort to explain what is going on, at least intuitively. As for the UI considerations, great feedback, I'll definitely take it all into account when re-designing. I'm open to additional suggestions from everybody.

Ultimately I'm glad that I was able to get the main point across. That is, that QR codes can take a lot more abuse than one might assume. Thanks for checking my work out!

boomskats•9mo ago
How can you say that you 'don't know pretty much nothing about QR codes' and that you 'feel like there's little point in interacting with a system you don't understand or not trying to understand', while feeling qualified enough to write a critique claiming a demo of said thing you know pretty much nothing about is incomplete?

You don't know what EC stands for but you have an opinion on when the error correction should be demoed? And the first thing you don't like are the icons?

OP, if I were you I would ignore this critique entirely. This is a fantastic demo. The usability was spot on (I learned a lot in a very short amount of time) and your /repos readme is _exactly_ what I wanted to read. It is perfectly executed.

I'm gonna dig into your code a bit more tomorrow, but you should be very proud of this. You have a bright future ahead of you.

Xiione•9mo ago
Thanks so much for your kind words! As a principle I try to at least listen to what everyone has to say, I wish I could make everybody happy but in the end I incorporate the feedback I'm convinced of/already agree with. Let me know if you have any thoughts on my code, and thank you for the github follow :)
gen3•9mo ago
Very cool work! I really like being able to see the blocks and directly interact with them. It's nice to feel out how the ECC works. I can see myself using this to draw custom QR codes in the future!
myself248•9mo ago
Oh, this is cool. My favorite part is being able to mouse over the health bars at the right, and see exactly which bits they draw from in the code itself.
teuobk•9mo ago
Awesome! I love seeing how the blocks are affected by twiddling bits.
pveierland•9mo ago
Super cool interface to explore. It took a bit of playing around with the UI to understand all the features. My only feedback would be to try to make the "Continue" part of the flow to get to the sandbox easier to discover.
Xiione•9mo ago
Thanks! The "continue" was one of those things that started off as a placeholder and didn't change much, I'll definitely be adjusting it.
solardev•9mo ago
This is really cool! Thanks for sharing!

Is there a way to get it to compute and visualize the MAXIMUM possible error rate for any given QR code? Like what is the greatest number and arrangement of pixels that could be altered before the QR code is no longer readable?

(Bonus: Is this a setting that can be controlled during QR code generation, based on version number or error correction level, etc.? Can you make some sort of huge and very complex QR code with a lot more redundancy than a smaller one?)

Xiione•9mo ago
Thanks for checking it out! Essentially, for any given QR code the maximum error rate is reached when you deplete every block's health bar to 1 remaining slice, making sure to invert every pixel in each codeword you've touched (the individual tetris-piece shaped chunks), and then introduce one more single pixel error in any block. This is actually independent of the arrangement of corrupted codewords within each block.

The amount of redundancy is determined solely by the specific version-ecLevel pair a code has. So, the code with the largest amount of redundancy (in bytes) is one that has version 40 and EC level H - a staggering 2.43kB of redundancy vs. 1.28kB of data! See this particular sample: https://qris.cool/decode?sample=135