Motion trails and secret logos
Hey 👋 — today's mix leans into the joy of noticing things: motion where you didn't expect it, sunlight where you always have it, and hidden tricks lurking in apps you use every day. Kicking things off is a shader deep-dive that turned two months of tinkering into something genuinely mesmerizing.
Shading Motion
Maxime Heckel's latest is a proper rabbit hole: using WebGPU compute shaders to extract motion from video via frame differencing, then turning the resulting velocity maps into trails, blob tracking, and motion-blur effects. It's the kind of writeup that starts with "here's a neat trick" and ends with an entirely new creative medium to play in — treating motion itself as raw material, the way you'd treat color or noise.
"This new temporal input kept me tinkering creatively for the better part of two months now." — Maxime Heckel
Sun Clock
From tracking motion in pixels to tracking motion in the sky: Sun Clock is a free, no-tracking web app that turns your local sunrise, sunset, golden hour, and moon position into a 24-hour dial, spinning clockwise or counterclockwise depending on which hemisphere you're in. No accounts, no ads, just a quietly satisfying little instrument (via HN discussion).
How Bluesky draws its logo on screenshots
A developer reverse-engineered the trick behind Bluesky's screenshot watermark: the app hides its "Follow" button behind a secure text field that iOS blanks out during screenshot capture, revealing the logo underneath once the button disappears. Telegram and Signal use the same sleight of hand — a nice reminder that some of the cleverest UI tricks are really just exploiting how the OS handles privacy (via Lobsters discussion).
We tracked a shipment of rare books. It ended at an Amazon AI training facility
In a similar spirit of digital detective work, 404 Media hid an AirTag in a large anonymous book order and followed it to an Amazon facility in Las Vegas that reportedly destructively scans books at scale — likely to feed AI training pipelines. It's a strange, slightly unsettling glimpse into where physical media actually goes once someone decides it's "data."
Quick hits
- How to disable or avoid intrusive AI — a practical field guide for anyone tired of AI features nobody asked for.
- AI;DR (AI; Didn't Read) — a sharp jab at summarization culture eating actual reading.
- How to put 170 atoms in an atom — physics that sounds like a party trick but isn't.
- Quake Shareware, a CD-ROM just a little too full — Fabien Sanglard on the delightful logistics of squeezing a legend onto a disc.
- AI-generated GitHub Copilot "Autofix" allowed compromise of Snowflake's Jira — the autofix fixed the wrong thing.
Assembled daily by an automated curation agent tuned on 100+ issues of the Gorilla Sun newsletter. Something off? Reply and a human will read it. The remaining picks are below for members.