hello. I'm halcy. here's some posts:

QR Codes that can be read multiple different ways

After seeing a Mastodon post about slightly messy QR codes recently, and another post pointing to a tutorial for how to read QR codes without a computer a while before that, I started messing around a bit with QR codes, and eventually ended up wondering if there are ways to make QR codes that scan with multiple different results, maybe exploiting the different quirks of different scanners or using camera tricks. It feels like something that somebody at some point would have tried.

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2026 Summer Seasonal Anime Preview

I like to watch seasonal anime, and posting about it. Instead of just posting a giant Mastodon thread, I’m going to try something new this season: Writing an aniblogger season preview post about the shows that I decided to give a try!

Lets start with the highly anticipated show …

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Transmitting data via ultrasound without any special equipment

There are secret messages flying all around you all the time, being transmitted via, most of the time, electromagnetic waves going from antenna to antenna.

Frame taken from the music video for Secret Messages, showing a man with big hair and aviators in front of a big sattelite dish, arms crossed

ELOs “Secret Messages” is a song about posting conspiracy theories via WiFi.

But what if you need to get a few bytes from device A to device B (one of the hard problems in computer science!) and you don’t feel like making sure they’re both connected to the same network? Well, fortunately, another channel is available to us - sound, or for a more fun and less-audible experience, ultrasound.

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Silly Mastodon apps

Just like used to be the case with Twitter, there are a lot of very nice third-party apps for Mastodon. I’m not neccesarily very good at making those, or at least do not usually feel like writing good software for fun most days, but I do maintain Mastodon.py …

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Mastodon.py in the browser!

Today, I learned that PyScript exists. PyScript is, at its core, some rigging to make Pyodide, a WebAssembly port of the CPython Python interpreter, real easy to use as a proper client-side web scripting tool. Just include one <script> tag and now <script type="py"> is a valid thing you can have in your website. Put Python code inside of it, interact with the DOM, the works. I think that rules and/or is kind of horrifying, depending. Obviously, for me, the immediate question was: Can this run Mastodon.py? And the answer is: Yes, very competently.

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I hope you've found what you were looking for. love, halcy.