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Changelog

All notable changes to JETCARP are listed here, newest first, in the style of Keep a Changelog. Before version 1.0, a release may still change the scene format, the command line, the scripting API and the MCP tools; 1.0 is the release that will declare them stable.

[0.4.0] – unreleased

The first public release.

What JETCARP 0.4.0 does

  • Tilings. Squares, hexagons and triangles, all eleven Archimedean tilings, the 1,248 k-uniform tilings up to k = 6, the 81 isohedral tile types, tiles you draw yourself, and the aperiodic Penrose (kites and darts, and rhombs), hat and spectre tilings, built on exact patches.
  • Automata. Life and the Life-like rules, Generations, Larger than Life, elementary rules on squares and hexagons, Langton’s ant and the turmites, WireWorld, Greenberg–Hastings, the cyclic and rock-paper-scissors rules, hodgepodge, sandpiles, Lenia and other continuous rules, JACA (Jimmie Rodgers’s annihilating two-sided Life), layered rules, Margolus block rules, rule tables and von Neumann’s 29-state automaton. Several can run at once, on shared or separate cell fields.
  • The app. A Quick Start menu of examples, an editor for worlds, tiles and unit cells, thirty palettes and your own, pictures and animations, and screensaver mode.
  • On the desktop. A background host that runs scenes as a live wallpaper (Windows, macOS, and GNOME through its own extension), on the GNOME lock screen, as the system’s screen saver (Windows and macOS), or as a still picture; see Wallpapers.
  • One program for every front end. jetcarp opens the app, and its subcommands are the command line, the background host (jetcarp host) and an MCP server for AI assistants (jetcarp mcp). Rhai scripts run worlds and parallel rule sweeps. All of them call one layer of 74 named operations, each with JSON Schemas for its input and output (jetcarp api list).
  • Searches. Nine search strategies (soup hunts on the plane and on bounded grids, a rule census, ants and turmites, movers on aperiodic tilings, large sandpiles, collisions, an evolutionary glider search, and an exploratory search over tilings, rule families and rules) run as resumable jobs whose results don’t depend on the thread count; see Search methods.
  • A verified pattern library. Every catalogued pattern is verified exactly, named by a content id that any program can recompute, and pinned to its tiling’s geometry and its rule family’s meaning, so a change to either is caught; see Library format.
  • Packs. Format 1.0 for sharing data: signed, content-addressed stores of Parquet tables and canonical JSON that other tools read without JETCARP, checked hash by hash and id by id on import; ratings go in only with each rater’s consent. See Packs and Pack format.
  • Reproducibility. Every run is a scene that replays bit for bit to a recorded state hash, and every picture JETCARP saves carries its scene; see Reproducibility.
  • Installing. Archives for Linux (x86_64 and ARM, glibc 2.28 or newer), Windows and macOS (Apple silicon and Intel), installers that check every download, Python wheels for pipx, uv and pip, a Homebrew tap, a Scoop bucket and crates.io, with a starter pack beside the program; see Installing JETCARP.
  • No network, no telemetry. JETCARP makes no network connections; see SECURITY.md.
  • This book, with a page on the history and credits of every automaton and tiling.

JETCARP grew out of CART, a private prototype Jimmie Rodgers built in early November 2026, and was reworked for release in a new repository with a fresh history; see How JETCARP was made.