JETCARP

Jimmie's Euclidean Tilings and Cellular Automata Research Program

JETCARP runs cellular automata on almost any tiling of the plane: squares and hexagons, all eleven Archimedean tilings, the 1,248 k-uniform tilings up to k = 6, 81 isohedral tile types, tiles you draw yourself, and the aperiodic Penrose, hat and spectre tilings. Several automata can run at once, on shared or separate cell fields. It has a graphical app, a command line, a scripting language, and a Model Context Protocol (MCP) server, plus tools that search for spaceships, oscillators and other patterns and keep verified catalogues of what they find.

Status: 0.4.0 is the first public release. Before 1.0, a release may still change the scene format, the command line, the scripting API and the MCP tools.

Installing

On Linux and macOS:

curl -LsSf https://github.com/jprodgers/jetcarp/releases/latest/download/jetcarp-installer.sh | sh

On Windows, in PowerShell:

Invoke-WebRequest https://github.com/jprodgers/jetcarp/releases/latest/download/jetcarp-installer.ps1 -OutFile jetcarp-installer.ps1
powershell -ExecutionPolicy Bypass -File .\jetcarp-installer.ps1

Or pipx install jetcarp (or uv tool install jetcarp); brew tap jprodgers/jetcarp then brew install jetcarp; scoop bucket add jetcarp https://github.com/jprodgers/scoop-jetcarp then scoop install jetcarp; or cargo install jetcarp. Every way, and what to know on each system, is in Installing JETCARP.

No telemetry. JETCARP makes no network connections: it does not check for updates, report crashes or collect statistics, and never sends anything anywhere. See SECURITY.md for what it does open (local sockets only) and how to report a security problem.

Building from source

JETCARP is written in Rust (1.95 or newer).

cargo build --release
cargo test --workspace --release

Licence

JETCARP is dual-licensed under the Unlicense and the MIT licence; use either. A few files derived from other people's work keep their own licences, listed in THIRD_PARTY_NOTICES.md.

Citing JETCARP

If JETCARP helps your research, please cite it. GitHub's Cite this repository button reads CITATION.cff. Every release is archived on Zenodo under 10.5281/zenodo.24191765, which resolves to the newest.

How JETCARP was made

Jimmie Rodgers designed JETCARP, chose its research directions, and tested it on Linux, Windows and macOS. All of its code was written by Claude Code, Anthropic's AI coding tool; the documentation describes who did what. Every simulation result JETCARP reports is checked by its own test suite or by exact verification (for example, exact recurrence for spaceships), but please treat it as you would any research software: check the results that matter to you.

Acknowledgements

Emily Teich rated hundreds of animated clips from JETCARP's exploratory search. Her ratings trained the score that decides which runs the search shows people, which brought her eye for what is beautiful into the search itself.

Craig S. Kaplan answered within hours, and generously, when asked whether JETCARP could use the code from Kaplan's Spectre visualizer, which had never been formally released: Kaplan made it available under the same BSD licence as Kaplan's hatviz. JETCARP's hat, spectre and isohedral tilings all rest on Kaplan's work.