January 19, 2026
Arcade in a text window?!
Show HN: An interactive physics simulator with 1000's of balls, in your terminal
Retro vibes, Braille beef, and AI-assisted ball chaos
TLDR: A Rust-made terminal app simulates thousands of colorful bouncing balls using Braille characters. Comments turned it into a nostalgia fest (Plasma Pong, 1992 demoscene), rekindled a “is Braille type?” debate, and praised the creator’s transparent AI-assisted workflow—proof that playful tech and open process can win hearts.
A dev just turned the humble command line into a mini arcade, and the comments are living for it. “Plasma Pong in the terminal” was the instant vibe, as nostalgia spilled over with shout‑outs to the Fishtro demo from 1992. Thousands of bouncing dots, wild colors, geysers—yes, this is happening inside a text window.
The clever trick? Using Braille characters to draw tiny balls. That sparked unexpected drama: one commenter dropped a story about a professor insisting “Braille isn’t type,” reigniting the Braille‑is‑type debate like it’s finals week all over again. Others cheered the choice as smart, accessible, and delightfully subversive.
There’s also meta‑gossip: the creator disclosed they built it with help from Claude (an AI assistant), and at least one reader praised the transparent prompt‑by‑prompt workflow and manual tweaks. Cue the classic internet split—AI skeptics side‑eye, pragmatists clap for shipping fast and sharing receipts.
Practical jokers piled on too, roasting slow terminals and crowning Ghostty the “arcade cabinet” for smooth frames. Between gravity sliders, color explosions, and saveable levels, the thread felt less like dev talk and more like a retro party with typography beef and AI workflow tea—ballin, indeed.
Key Points
- •“ballin” is a Rust TUI app that simulates thousands of balls using Rapier 2D, achieving 120+ FPS on up to 10,000 balls.
- •Braille Unicode is used to render fine-grained ball visuals within terminal constraints.
- •Interactive controls include clicking for bursts, geysers via keys 1–6, spawning balls, and pinball tilt via resizing or arrow keys.
- •Users can adjust physics (gravity, friction, forces), add and color shapes, and save/load levels as JSON.
- •Installation is available via GitHub Releases for macOS, Linux, Windows, or via cargo; high-FPS emulators like Ghostty are recommended.