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The Global Interface of Connectivity: How Connection Became an Interface

https://medium.com/@smoking2man/the-global-interface-of-connectivity-how-connection-became-an-int...
1•Aldus551•48s ago•0 comments

A 27-byte telemetry response nobody reads freezes Claude Desktop every two days

https://blog.dfb.sh/blog/claude-desktop-freeze/
1•brandon_bot•2m ago•0 comments

AI Productivity Gains Mainly Benefit People at the Top

https://nelson.cloud/ai-productivity-gains-mainly-benefit-people-at-the-top/
1•nelsonfigueroa•3m ago•0 comments

Every Flight Is Grounded on Day Trump Admin Installed AI Controls

https://www.thedailybeast.com/faa-abruptly-grounds-all-flights-for-first-time-since-911
1•madihaa•4m ago•0 comments

After 26 years, the US has lost its measles elimination status

https://www.cnn.com/2026/11/13/health/us-measles-elimination-status
1•madihaa•5m ago•0 comments

Why C# over C for Systems Programming

https://github.com/OnurGumus/bflat_test
1•reverseblade2•7m ago•0 comments

Windows 11's modern Run box arrives in December. Nobody clicked Browse button

https://www.windowslatest.com/2026/11/14/windows-11s-modern-run-box-arrives-for-everyone-in-decem...
1•thunderbong•12m ago•0 comments

Borland C++ 2.0 Compiler Source Reconstructed

https://hackaday.com/2026/11/13/borland-c-2-0-compiler-source-reconstructed/
1•fork-bomber•13m ago•0 comments

Show HN: VPN Manager

https://github.com/DennySORA/vpn-manager
1•dennysora-main•15m ago•0 comments

Anatomy of a Git pre-commit Hook

https://georgestocker.com/2019/10/31/anatomy-of-a-git-pre-commit-hook/
1•ankitg12•17m ago•0 comments

Firefox Focus

https://www.firefox.com/en-US/mobile/focus/
1•appwiz•28m ago•0 comments

Ode for Trump

https://salmagundi.skidmore.edu/articles/2034-ode-for-trump
2•classified•32m ago•0 comments

FAA TDM-to-IP Migration (2015) [pdf]

https://www.faa.gov/sites/faa.gov/files/air_traffic/technology/cinp/fens/tdm-to-ip_migration_2015...
1•gr33nq•35m ago•0 comments

Old tech blamed for the ground stop that caused flight chaos: It got overloaded

https://www.npr.org/2026/11/13/nx-s1-6040403/faa-nationwide-groundstop-airports
3•geox•36m ago•0 comments

ShieldFont – Protect human muffins by poisoning unauthorized AI starfish

https://shieldfont.org/
2•negura•39m ago•0 comments

Will Anthropic Grow into Its Compute Bill?

https://twitter.com/OrnnExchange/status/2119839768355778637
1•gmays•40m ago•0 comments

Businesses suffering a loss from Microsoft outage could make insurance claim

https://www.rnz.co.nz/news/business/2593252/businesses-suffering-a-loss-from-microsoft-outage-cou...
3•billybuckwheat•41m ago•0 comments

Formal Verification Is Not Verifiable: Bouba and Kiki Software

https://alperenkeles.com/posts/formal-verification-is-not-verifiable/
1•matt_d•46m ago•1 comments

Kim, Claude and Yaht-C

https://www.engineersneedart.com/blog/yahtc/yahtc.html
1•chmaynard•46m ago•0 comments

Israeli airstrike on Nasser hospital in Gaza killed surgeon and others

https://www.theguardian.com/world/2026/nov/12/israeli-airstrike-nasser-hospital-gaza-kills-surgeon
3•0x54MUR41•51m ago•0 comments

Need a guy to make short form videos

https://www.facebook.com/p/Alina-James-61593204405007/
1•yoursocialguyra•51m ago•0 comments

Air traffic control modernization effort needs (Sep 14, 2026)

https://files.gao.gov/reports/GAO-26-107992/index.html?pubDate=20260922&utm_source=chatgpt.com
2•giuliomagnifico•53m ago•0 comments

Workday Down for thousands of Companies

https://www.sfchronicle.com/tech/article/workday-outage-employees-accounts-22529939.php
4•Madmallard•55m ago•1 comments

Transforming Ripgrep's Documentation with AI Automation and MkDocs

https://entropicdrift.com/blog/mkdocs-drift-automation/
2•ankitg12•1h ago•0 comments

I Built a $300 Robot Hand With 18 Motors [video]

https://www.youtube.com/watch?v=Sk0x-xMNQks
3•olalonde•1h ago•0 comments

Inquestra – Local-first lab notebook with native Web Serial DAQ

https://inquestra.org
2•ImKaleb•1h ago•0 comments

Invention Changes Everything [video]

https://www.youtube.com/watch?v=DJCN-tjBceA
2•pillars•1h ago•0 comments

Where to find Canadian government tenders: every portal compared, free

https://pubsec.pro/blog/find-government-tenders-canada
2•wren_sato•1h ago•0 comments

Lychee: Check Local Links

https://lychee.cli.rs/overview/
2•ankitg12•1h ago•0 comments

I reverse-engineered Instinct. Here's the whole machine

https://twitter.com/nizzyabi/status/2120194267066863738
2•gmays•1h ago•0 comments
Open in hackernews

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

https://qris.cool
109•Xiione•1y 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•1y 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•1y 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•1y 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•1y 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•1y 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•1y 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•1y ago
Awesome! I love seeing how the blocks are affected by twiddling bits.
pveierland•1y 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•1y 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•1y 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•1y 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