PGSimCity - How PostgreSQL Works

https://nikolays.github.io/PGSimCity/og.png
An explorable 3D city that shows how PostgreSQL actually works — backends, shared buffers, WAL, checkpoints, autovacuum and replication, all running live in your browser.

Show HN: Physically accurate black hole you can put in your room

this is a simplified viz · for science-grade rendering → Synchray.jl

Decker, a platform that builds on the legacy of Hypercard and classic macOS

Decker is a multimedia platform for creating interactive documents with sound, images, and scripted behavior, available for web browsers and various operating systems. It features a simple and intuitive interface, a scripting language named Lil, and supports sharing and collaboration through web pages and source control tools.

Scriptc by Vercel: TypeScript-to-Native compiler, no JavaScript engine in binary

https://opengraph.githubassets.com/20b689b4a20d96139781d975d047209fe53510e6451778db228152521844c355/vercel-labs/scriptc
scriptc compiles ordinary TypeScript into small, fast native executables without Node or JavaScript engine, allowing for type-checked and statically compiled code with native performance. The tool supports a wide range of TypeScript features, including generics, async/await, and classes, and provides differential testing and memory-safety checks to ensure correctness and security.

French firefighters face 'pyrocumulonimbus' for first time

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I wanted a clock that never needed setting. Things escalated

https://cdn.arstechnica.net/wp-content/uploads/2026/07/JT3A6491.jpg
The user created a custom bedside clock using a Raspberry Pi, 3D printing, and a seven-segment display, with the help of a Large Language Model (LLM) for coding and CAD work. The project involved soldering, iterating through design revisions, and incorporating a neutral density filter and smoked acrylic to achieve the desired dimness and aesthetic.

We have proof automation now

The user discusses the benefits and challenges of dependently-typed languages like Lean, which can encode and enforce complex invariants, but require significant proof effort. They explore the potential of combining Lean with large language models (LLMs) to automate proof generation and make dependent types more practical for quotidian software engineering.
https://www.techspot.com/images2/news/bigimage/2026/07/2026-07-26-image-4.jpg
A US federal case is raising questions about GrapheneOS, a privacy-focused mobile operating system, after prosecutors accused its user of destroying evidence. The case centers on whether the operating system's features, designed to protect user privacy, can be considered a crime.

Htmx 4.0, the first JavaScript library to release exclusively on the Game Boy

https://imgproxy.fourthwall.dev/OXz1JISnUSNzMq3ZSDa53XiVmDMWaqcJ0CQkQBRdBV8/w:1920/sm:1/enc/EwYqh2EzXPAU7H04/BMXqquHCApkGKbGh/LoFc40D31bsD6gv4/lJ5EIYZduCxm8qAG/13LlpWyyziWbLs7D/Xi4TfM5SZiC5kSsq/f-tOQtISSQdUx14H/3kaNrBbOOijmZBov/fuUJOdCo4m-eyLcf/7A97CwuTeNBI_GsD/K81ThuM9c3cS1p--/oRP_PAY7b_W4O2kr/rRJzjKSc6clktadC/XRtwNg.webp
Four levels of pickle-collecting excitement. Squish client-side JS down to size, avoid slop and, if you have the skills, defeat Warren to unlock the htmx 4.0 source code! Quality is guaranteed. If there is a print error or visible quality issue, we'll replace or refund it. Because the products are made to order, we do not accept general returns or sizing-related returns.

Introduction to Data-Oriented Design [pdf]

Design is compromise

https://stephango.com/assets/covers/design-is-compromise.png
Compromise is a necessary part of decision making and design, where you prioritize one thing over another to achieve a balance between competing desires. Making difficult choices and being opinionated about tradeoffs is what defines good design and makes products exceptional.

Simulate cassette tape audio profiles using FFmpeg

https://raw.githubusercontent.com/AARomanov1985/Audio-Cassette-Simulation/master/assets/cassettes.jpeg
# Convert local audio files (mp3, ogg, m4a, aac) ./convert_cassette_*.sh # Record a live web stream into segment files ./record_stream_cassette_*.sh [STREAM_URL]

Fonts In Use – Find out where a font is used

https://assets.fontsinuse.com/static/use-media-items/298/297113/thumb/6a6647e0/50113523612_79165e463b_4k.jpeg
These are the most common typefaces in the database, but there are many more. Try a search!

The Usefulness of Useless Knowledge (1939) [pdf]

Teaching Kids Forth

https://gracefulliberty.com/articles/teaching-kids-forth/abacus.jpg
The author taught middle and high school students programming using the stack-oriented language Forth, despite its uncommon use, to give them a unique learning experience. The students created their own art in the Forth environment, demonstrating their understanding of the language.

Show HN: CheapSecurity – Lightweight, Self-Hosted CCTV for Linux SBCs

https://opengraph.githubassets.com/9cd973e59933bcac83b641420e24cb242c02559433bd32eeab141b4d682ddb4c/gmrandazzo/CheapSecurity
This project provides a lightweight, self-hosted CCTV solution for Linux-based devices and standard USB webcams, offering an affordable and privacy-focused alternative for home monitoring. It stores video data locally, eliminating the need for third-party cloud subscriptions and ensuring data remains under user control.

How to Write English Prose

https://thelampmagazine.com/images/the-lamp-logo-mark.png
The author discusses the beauty and complexity of English prose, particularly in the 17th century, and argues that the current trend of simplicity and minimalism has led to a decline in writing quality. He offers 12 rules for writers, emphasizing the importance of using precise and evocative language, avoiding clichés and over-simplification, and cultivating a sense of elegance and verbal cleverness.

Go Analysis Framework: modular static analysis by go team

https://pkg.go.dev/static/shared/gopher/pilot-bust-1431x901.svg
The Go analysis package provides a modular static analysis framework that allows developers to define and reuse analysis functions, known as checkers, which can be easily selected and incorporated into various driver programs. The framework includes a common interface, Analyzer, which describes an analysis function, and a Pass type that provides information to the analysis function and allows ...

History of John Backus's functional programming project [draft]

John Backus explored functional programming languages from 1969 to 1991, aiming to simplify programming. He developed the Red language, which featured a family of expression-oriented languages with simple rewrite rules.

Plasma Tunnels Reveal How Dying Satellites Fall to Earth

https://spectrum.ieee.org/media-library/close-up-of-a-burnt-metal-cylinder-its-exterior-is-charcoaled-but-the-center-appears-mostly-in-tact.jpg?id=67521149&width=1200&height=750
Researchers in Germany are melting satellite chunks in high-temperature plasma wind tunnels to study space debris reentry. Their tests reveal concerns about ozone depletion and atmospheric changes due to incinerated satellite ash.

The relay market powering token resellers and fraud

https://storage.googleapis.com/ployai/2eb2235a-6b78-4d32-9713-f051311d8809/user/4ab64ff4-daily-lottery.webp
The token economy has become a breeding ground for abuse, with a complex ecosystem of relays, account pools, and merchants that enable cheap tokens and model distillation, resulting in millions of dollars in losses for companies. To combat this, companies can raise the cost of entry, monitor for suspicious behavior, and throttle attackers quietly, but ultimately, fraud is a constant ...

The New AI Superpowers: Focus and Followthrough

https://substackcdn.com/image/fetch/$s_!R31O!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F7a57282a-143c-41d8-a777-084d8e097340_498x498.gif
The author initially thought AI would make them underworked and burnout-free, but instead, they created more projects and experienced burnout. They learned to focus on a few key projects and deliver high-quality work by being ruthlessly focused and prioritizing what matters.

I learned PCB design, 3D printing and C just to listen to music

https://pentaton.app/images/lp/board.png
User built a streamer that resembles a vinyl sleeve, using a 17" industrial LCD and Radxa CM3 single-board computer. The device displays high-resolution artwork from AirPlay streams and can be powered via USB-C PD, consuming less than 2 watts when off.

Show HN: Reverse Minesweeper

https://sunflowersgame.com/sunflower.png
The game has five tiers: Basic, Easy, Medium, Hard, and Extreme, each with increasing difficulty and logic complexity. Grids are scored 0-100 based on their sub-metrics, with higher scores indicating harder puzzles and longer estimated solve times.

How to Block Some of the Bots

https://wordpress-cookiebanner.noyb.eu/wp-content/uploads/2026/07/header.png
The EU Commission proposed a solution to cookie banners, allowing users to set privacy preferences in their browser once, but the tracking industry is pushing back. Users can help by contacting their representatives in the European Parliament or national government to express their frustration.

Some more things about Django I've been enjoying

You're learning Django to build a website with an SQL database and backend rendering of HTML. You're finding it more achievable than using Go's standard library or Flask, and appreciate features like query set classes and template filters.

Using sed to make indexes for books (1997)

A sed script was created to convert a sorted file of index terms and page numbers into a format ready for printing, but it failed when encountering a line without a semicolon. The problem was fixed by adding a check at the beginning of the script to halt the process if any line is missing a semicolon.

What's Under Your Feet in New York City?

https://images.squarespace-cdn.com/content/55ac34e4e4b0170ef54be632/1784649791214-TPZGNTPUA52UUZ6H53Q4/vlcsnap-2026-07-20-22h37m48s985.png?format=2500w&content-type=image%2Fpng
New York City's underground infrastructure is a complex network of water, electrical, steam, gas, and telecommunications lines that provide essential services to its residents. The city's unique infrastructure is a result of its dense population and the need for reliable and efficient services, but it also poses significant engineering challenges and requires ongoing maintenance and upgrades.
The University of Chicago Law School is adapting its curriculum to the AI era by developing AI-resilient pedagogy, elevating essential human skills, and teaching responsible AI use. The school is implementing policies across its curriculum, including prohibiting electronic devices in 1L classrooms, introducing AI skills training in 1L Legal Research and Writing, and experimenting with ...