Ask HN: What's the most creative 'useless' program you've ever written?

Hacker News Discussion ↗

Playful, “useless” programs—from Mondrian-style image generators and Markov bots to esoteric language interpreters, particle sims, and prank scripts—are celebrated as some of the most memorable things developers have ever built. Commenters share dozens of small experiments, art pieces, hacks, and overengineered toys, arguing that even when they have no obvious practical purpose, these projects sharpen skills, rekindle joy in coding, and sometimes unexpectedly turn out to be useful.

Overall theme: “Useless” as core hacker practice

  • Thread is a long show-and-tell of playful, non‑practical projects.
  • Many argue this kind of tinkering is central to “hacking”: exploring ideas, constraints, and tools for their own sake.
  • Several note that ostensibly useless projects later gained real utility.

Visual, artistic, and generative projects

  • Numerous graphic toys: Mondrian/Piet‑style image generators, fractals and Mandelbrot zoomers (including touch‑zoom), particle/fluid simulations, kaleidoscopes, ray tracers, 3D ASCII cubes, and vector/pen‑plot art engines.
  • Many personal sites use interactive art (villages, perlin‑noise backgrounds, particle fields, animated ASCII, clocks that encode time as colors or digits).
  • Projects map images into other media: SVG primitives, Excel cell colors, pixel mosaics, fireworks text, photo‑reconstruction from rectangles, image‑derived primes, AI clocks, etc.

Languages, interpreters, and deep esoterica

  • People implement interpreters/compilers for BASIC, Forth, C subsets, Brainfuck, Lua, C in Python, esolangs like Piet and Funciton, SUBLEQ and FRACTRAN, and type‑level programming in TypeScript.
  • Some golfed or obfuscated entries (IOCCC, tiny RISC‑V/MIPS emulators, 4004 Linux stunt) are celebrated as “beautifully pointless.”
  • Others build abstract math toys (ordinal notation systems, combinator calculi, binary lambda calculus, exotic calendars).

Bots, generators, and odd UIs

  • Markov bots trained on chat logs, issue trackers, or political tweets mimic speech with absurd results.
  • “Fake activity” tools simulate busy terminals, scrolling logs, or Git histories.
  • Novel encodings: IPs as haiku, emoji short URLs, ASCII bonsai, QR‑to‑QR messaging, comment randomizers, etc.

Games, simulations, and physical gags

  • Many write clones or twists on classic games (Tetris, roguelikes, match‑3, Minesweeper variants, Pong as cellular automaton, Sudoku solvers).
  • Others build galactic or ecosystem simulations, particle “water,” demo‑scene intros, and sound‑based visualizations.
  • Hardware hacks include door or tunnel sensors playing Mario sounds, heart‑rate displays, and “magic 8‑ball” devices.

Pranks, Easter eggs, and workplace antics

  • Stories include subtle window‑nudging hacks, DVD drive openers, joke CLI tools, Slack/IRC bots, and hidden Easter eggs in shipped software.
  • Some automate annoyance (fake alerts, spinning CPU to warm a snack, trolling managers with over‑engineered helpers).

Learning and unexpected usefulness

  • Many describe these as vehicles to learn graphics, CV, numerics, compilers, networking, or JS optimization.
  • A recurring motif: projects later find niches (e.g., analog clock readers adapted for pressure gauges, color‑palette extractors for design, custom CAD in PostScript, niche automation tools).