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ASCII fluid dynamics -- IOCCC2012 endoh1.c

Name: ASCII fluid dynamics -- IOCCC2012 endoh1.c
Description: A 3-minute demo of a tiny IOCCC 2012 winning C program that simulates fluid dynamics in an 80x25 terminal, using any text (including its own source) as input. The video shows the simulation running to Handel's Water Music.

Yusuke Endoh Demos

Open on YouTube First HN thread

3 HN users recommended this demo in 3 different months between 2018 and 2025.

2007–2026

3 strong recommendations 3 citations HackerTube score 4.5

Commenters repeatedly point to it as an astonishing, beautiful piece of obfuscated-C code golf.

A 3-minute demo of a tiny IOCCC 2012 winning C program that simulates fluid dynamics in an 80x25 terminal, using any text (including its own source) as input. The video shows the simulation running to Handel's Water Music.

Pull quote: “truly a work of art” (HN, 2023)

Also tagged: obfuscated c programming, ioccc, fluid simulation, ascii art, c, code golf

What Hacker News said

6 labeled comments from the HN archive; up to 20 are kept per video, favoring different commenters. Each one links back to the original thread.

Strongly recommends yung_steezy May 2022 under An uroboros program with 100 programming languages

Astonishing C program approximating fluid dynamics from any text input.

Yusuke Endoh is a god amongst men. His C program which creates an approximation of fluid dynamics from any text input is insane - [this video]

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Strongly recommends daptaq October 2022 under A Ruby program that generates itself through a 128-language quine loop

ASCII fluid dynamics IOCCC entry that astonished the commenter more than the quine.

This was written by Yusuke Endoh, who also wrote this submission to the IOCCC that I remember being arguably more astonished when I saw it for the first time: [this video] (ASCII fluid dynamics).

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Strongly recommends 6502nerdface February 2023 under 2D Liquid Simulator with Cellular Automaton

Compact C source runs full fluid sim and can take itself as input.

My favorite 2D liquid simulator is this IOCCC2012 submission [1]... simply astonishing. That is the source file shown at the beginning of the video... it compiles without warnings, runs a full blown fluid dynamics sim with surface tension and everything, can take itself as its own input... truly a work of art. [1] [this video]

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Citations, criticism and jokes

Cites it bewuethr May 2018 under Asciinema – Record and share your terminal sessions

Demo of the IOCCC ASCII fluid program using its own source as input.

These remind me of the ASCII fluid submission [0] at IOCCC 2012 [1] by Yusuke Endoh. The source [2] itself can be used as an input to the program (see video [3]), and he also made a colour version [4]. [0]: [link] [1]: [link] [2]: [link] [3]: [this video] [4]: [link]

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Cites it tromp May 2024 under Fast real time fluid simulator based on MPM algorithm

Shows the concise IOCCC fluid simulator running.

The IOCCC also featured a very concise fluid simulator [1] [2], which can be seen in action in this video [3]. [1] [link] [2] [link] [3] [this video]

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Cites it pwnfunction October 2025 under Show HN: ASCII Drawing Board

Cited as an example of fluid simulation applied to ASCII drawings.

is this opensource? adding a cool fluid simulation to whatever you draw would be really fun. its like one of those ioccc vids - [this video]

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