# The community's toolbox, 2007–2026 > Nineteen years of community software for Eternity II (manual-placement GUIs, editors, public solvers, generators and viewers), plus the quieter layer that made them interoperate: e2pieces.txt, CRC-16 checksums, and the board-in-a-URL format that became the lingua franca. A reference census, with every tool sourced to the message that announced it. - Canonical page (with interactive figures/demos): https://eternity2.dev/research/build/tooling/ - Updated: 2026-07-02 - Source: The e2pieces.txt file format written down (John Morrison), eternity2@groups.io, 2007-12 — https://groups.io/g/eternity2/message/3571 - Source: The CRC-16 checksum scheme, launch week, eternity2@groups.io, 2007-07 — https://groups.io/g/eternity2/message/1063 - Source: eii4me's Manual Placement Program, the first shared GUI tool, eternity2@groups.io, 2007-12 — https://groups.io/g/eternity2/message/3541 - Source: E2Lab is born (Fred / Eternity Blogger), eternity2@groups.io, 2009-10 — https://groups.io/g/eternity2/message/7071 - Source: Jef Bucas launches e2.bucas.name, the board viewer, eternity2@groups.io, 2019-11 — https://groups.io/g/eternity2/message/9955 - Source: libblackwood published (Jef Bucas), eternity2@groups.io, 2020-11 — https://groups.io/g/eternity2/message/10078 - Source: Survey of e2pieces.txt files: “it's a mess!” (Vasily V.), eternity2@groups.io, 2023-03 — https://groups.io/g/eternity2/message/11033 - Source: e2.bucas.name (Jef Bucas), the community viewer and today's shared board format — https://e2.bucas.name --- The Eternity II community wrote a lot of software: solvers, of course, but also manual-placement programs for hand-solvers, board editors, fill-path explorers, puzzle generators, renderers and viewers. This page is the census of that toolbox: who built each tool, when, what it did, and where it lives now. The [history pages](/research/community/hunt) tell the story these tools appear in, and the [solver pages](/research/build/solvers) cover the algorithms. Dead links are stated as dead; nothing here is a download recommendation. One constraint shaped the contest years. In August 2007 the puzzle's inventor claimed copyright on the piece designs and threatened entrants who circulated them ([msg 1342](https://groups.io/g/eternity2/message/1342)), so the norm became that community tools did not ship the pieces. Every program below expects you to type in your own set: "a rite of passage into the E2 fraternity. We ALL did it.", as Alan O'Donnell put it when the argument flared for the nth time ([msg 7578](https://groups.io/g/eternity2/message/7578)). The moderators, for their part, removed piece files from uploaded tool archives when authors slipped ([msg 7609](https://groups.io/g/eternity2/message/7609)). That is why the toolbox has a second, less visible layer: shared file formats and checksum protocols that let tools and people interoperate without anyone transmitting the piece data. Both layers are catalogued here. That norm has since eroded. Filled-in `e2pieces.txt` files circulated on GitHub for years (Vasily V. surveyed "every one he could find" in 2023, below), and open piece-set libraries followed: jwortmann's Eternity2Puzzles.jl and Dobrogost's eii-puzzles both carry the set. The edge-adjacency numbers are, in practice, public. Our own [starter kit](/research/build/toolkit) ships the set for the same reason: reproducibility without a manual transcription step. ## 2007–2008: launch tools The first tools predate the puzzle. Brendan Owen posted C++ source for generating Eternity-II-like puzzles in January 2007, six months before launch; that code is the seed of the entire benchmark culture ([msg 41](https://groups.io/g/eternity2/message/41)). Sergio "Zerjillo" Alonso uploaded a corpus of 10,080 generated test boards plus the generator and a statistics spreadsheet that spring ([msg 201](https://groups.io/g/eternity2/message/201), [msg 202](https://groups.io/g/eternity2/message/202), [msg 203](https://groups.io/g/eternity2/message/203)). Owen had also written a computer-vision program to read scanned piece panels, which digitized the real puzzle on launch eve ([msg 789](https://groups.io/g/eternity2/message/789), [msg 1054](https://groups.io/g/eternity2/message/1054)). The launch year's flagship was Dave Clark's **eternity2.net**, the BOINC-based [distributed solver](/research/build/faster/distributed-solving) ([msg 756](https://groups.io/g/eternity2/message/756)). It mattered less for its computing (the project closed in December 2007 having changed nothing, [msg 3511](https://groups.io/g/eternity2/message/3511)) than for its legacy: its client's `e2pieces.txt` / `e2hints.txt` files became the community's standard formats (below), its solver and data files were preserved in the group archive with Clark's blessing ([msg 3633](https://groups.io/g/eternity2/message/3633)), Bob Cousins shipped community-patched "rmc" builds of the solver ([msg 3654](https://groups.io/g/eternity2/message/3654)), and Clark open-sourced his personal R&D program, a research solver that could export SAT and LP encodings and generate E2-like puzzles ([msg 3716](https://groups.io/g/eternity2/message/3716)). The first fast *public* backtracker was Marc Lebel's C++ solver at squaro.fr, whose internals the list dissected in the era's best solver-engineering thread ([msg 1704](https://groups.io/g/eternity2/message/1704)). Rendering was solved early and cleverly. Henk van der Griendt photographed his own pieces and built an HTML visualiser from the pictures ([msg 2499](https://groups.io/g/eternity2/message/2499)); Ignacio Ruiz de Conejo went further with **EPiecesV2.ps**, a PostScript program that renders any 16×16 board or 256-piece set from the official edge numbering. He shipped the *renderer* rather than the piece data, precisely to stay on the right side of the copyright line ([msg 2616](https://groups.io/g/eternity2/message/2616)). Owen adopted it for his own visualisation ([msg 2617](https://groups.io/g/eternity2/message/2617)). The non-programmers got their tool in December 2007: eii4me's **Manual Placement Program** (EternManShare.EXE), a VB6 GUI for placing pieces by hand, released with source and iterated to version S3.00 within eight days on community feedback ([msg 3541](https://groups.io/g/eternity2/message/3541), [msg 3719](https://groups.io/g/eternity2/message/3719)). And in February 2008 Yannick Kirschhoffer released **Eternity II Editor 1.0.0**, a cross-platform Java board editor that would become the longest-lived tool of them all ([msg 4544](https://groups.io/g/eternity2/message/4544)). ## 2008–2010: the editor era and the open-source wave The central release of the era was Louis Verhaard's **eii**, the solver that won the only prize money Eternity II ever paid. Published in September 2008 at fingerboys.se with the words "I am stuck and my only hope to improve my best score is by using brute force" ([msg 5940](https://groups.io/g/eternity2/message/5940)), it was distributed as a binary for volunteers to run; the documentation and a decoder for its `.eii` output files followed in January 2009, along with the disclosure that users had found 467 more than forty times ([msg 6275](https://groups.io/g/eternity2/message/6275)). Its hosting is a lesson in link rot: fingerboys.se was Verhaard's band's website and folded with the band ([msg 7446](https://groups.io/g/eternity2/message/7446)), so in January 2010 the solver moved unchanged to [shortestpath.se/eii](http://www.shortestpath.se/eii/), his own site and its long-term home ([msg 7439](https://groups.io/g/eternity2/message/7439)). Hobbyists were still running it at 466-level scores in 2011 ([msg 8840](https://groups.io/g/eternity2/message/8840)), and veterans were still walking newcomers through `eii.exe` in 2021 ([msg 10202](https://groups.io/g/eternity2/message/10202)). The machine itself has [its own solver page](/research/lab/experiments/louis-verhaard/eii). Around it, a whole shelf filled in: - **E2_Manual**, trans.spam (Thomas)'s DirectX manual-placement program, at v1.0.0.18 by mid-2008 ([msg 5686](https://groups.io/g/eternity2/message/5686)), moved to a SourceForge project with binaries and source in June 2009 ([msg 6765](https://groups.io/g/eternity2/message/6765)). - **Eternity II Editor** grew from editor to solver: 1.3 in March 2009, then 1.4.0 with the real E2 patterns, a built-in solver and a random board generator ([msg 6594](https://groups.io/g/eternity2/message/6594), [msg 6679](https://groups.io/g/eternity2/message/6679)), then v1.5 within a day of a user's feature requests ([msg 6978](https://groups.io/g/eternity2/message/6978)). It lives at SourceForge (sourceforge.net/projects/eternityii); Kirschhoffer resurfaced in 2012 still offering help with the code ([msg 9064](https://groups.io/g/eternity2/message/9064)), and in 2023 Bruno Gauthier's 460 (the best five-clue board until 2026) was "made with my own program and Eternity II Editor" ([msg 11074](https://groups.io/g/eternity2/message/11074)), converted to the shared viewer format by Peter McGavin ([msg 11081](https://groups.io/g/eternity2/message/11081)). - **E2Lab.** Fred ("Eternity Blogger") published a Windows editor+solver in October 2009 and iterated almost daily ([msg 7071](https://groups.io/g/eternity2/message/7071)); it took the E2Lab name at v1.0.0.20 ([msg 7148](https://groups.io/g/eternity2/message/7148)), and v1.0.0.21 removed a "magic button" explicitly "to respect the game rules" ([msg 7150](https://groups.io/g/eternity2/message/7150)). E2Lab is also the source of the community's canonical tooling-reliability lesson: in December 2009 a user reported a popup announcing a 471 on a board that was never saved, an unverifiable claim that still haunts records discussions ([msg 7284](https://groups.io/g/eternity2/message/7284)). - **e2walker.** Philippe Coustaux's fill-path explorer, in the group Files section since August 2007 ([msg 2313](https://groups.io/g/eternity2/message/2313)), revised by Ole Knudsen ("Kron") and, when the list took inventory in 2009, still "the only program of its kind": a solver that lets you specify an arbitrary 256-step fill path ([msg 7056](https://groups.io/g/eternity2/message/7056), [msg 7067](https://groups.io/g/eternity2/message/7067)). - **WhichWayToGo.jar.** okifinoki (Benjamin)'s GUI for scoring candidate fill paths by expected options per placement; three independent implementations converged on its statistics within the thread ([msg 6572](https://groups.io/g/eternity2/message/6572)). His graphical puzzle generator E2Generator.jar had joined the Files area the previous autumn ([msg 6036](https://groups.io/g/eternity2/message/6036)). - **Open solver source** arrived in a wave: Markus Zajc's C++ constraint-propagation solver ([msg 6748](https://groups.io/g/eternity2/message/6748)); Martin Hapl's Java backtracker at hapl.net, surfaced by the list and community-profiled from 1.2M to 2.9M iterations/s ([msg 6794](https://groups.io/g/eternity2/message/6794), [msg 6916](https://groups.io/g/eternity2/message/6916)); snazzyflapper's C# task-parallel solver, promptly re-uploaded without the piece file the moderators flagged ([msg 7606](https://groups.io/g/eternity2/message/7606), [msg 7610](https://groups.io/g/eternity2/message/7610)); and doc_s_smith's **Eternity II Java Toolbox**, a five-tool suite (configurable backtracker, constraint-driven placement, mismatch-tolerant search with swap repair, Monte-Carlo node estimator, fill-strategy finder) that marked the Eternity I veteran's return in June 2010 ([msg 7755](https://groups.io/g/eternity2/message/7755)). ## 2011–2018: the quiet years' tools As the contest died, the tools got stranger and more personal. Dan Hansen, after "4 engrossing years" of E2 algorithms, shipped **Edge Match Puzzles** for iPhone, the first time the community's expertise became a consumer product ([msg 8943](https://groups.io/g/eternity2/message/8943)); Tony Wauters's academic group released an Android edge-matching app ([msg 9057](https://groups.io/g/eternity2/message/9057)). Juraj Pivovarov uploaded a scan-order visualizer, self-deprecatingly billed as a "total waste of time" ([msg 9013](https://groups.io/g/eternity2/message/9013)). Theory became a document: Peter McGavin's complex_theory.pdf, the LaTeX transcription of Owen's model, was in the group Files by 2013 ([msg 9188](https://groups.io/g/eternity2/message/9188)). The open-source torch passed to David Barr: an OpenCL solver published on GitHub in 2015 ([msg 9360](https://groups.io/g/eternity2/message/9360), [msg 9367](https://groups.io/g/eternity2/message/9367)). The repo, github.com/david3x3x3/eternity2, is still the era's most reused codebase, followed by Raspberry Pi cluster builds with a public status page ([msg 9582](https://groups.io/g/eternity2/message/9582)), a Python-in-the-browser solver via Pyodide ([msg 9854](https://groups.io/g/eternity2/message/9854)) and dancing-links experiments with visualizations ([msg 10095](https://groups.io/g/eternity2/message/10095), [msg 10100](https://groups.io/g/eternity2/message/10100)). The web got its first solver playground too: Guillaume L.'s browser backtracker at 16x16tetravex.xyz, whose instant solves collapsed to "never-ending" the moment puzzles were regenerated with E2-like colour statistics, a live demonstration of where the difficulty lives ([msg 9449](https://groups.io/g/eternity2/message/9449), [msg 9458](https://groups.io/g/eternity2/message/9458)). ## 2019–2026: the modern stack The modern toolchain begins with a rescue. When Yahoo announced it would erase Groups content in 2019, the migration to groups.io carried the messages, files and photos across with weeks to spare ([msg 9934](https://groups.io/g/eternity2/message/9934)), which is why the Files-area tools above still exist at all, behind the group's membership wall. Two weeks after the migration, Jef Bucas launched **[e2.bucas.name](https://e2.bucas.name)**: SVG-rendered boards encoded entirely in URL parameters ("since the parameters are after the '#', nothing is actually transmitted to the server"), with a drop-down of best boards that quietly became the community's record book ([msg 9955](https://groups.io/g/eternity2/message/9955)). A Clues page answering the perennial hint-piece questions followed in 2021 ([msg 10082](https://groups.io/g/eternity2/message/10082)), and a revamp with keyboard shortcuts and score display in 2022 ([msg 10590](https://groups.io/g/eternity2/message/10590)). Virtually every partial shared since is an e2.bucas.name URL. The record-solver line is a three-repo story. Joshua Blackwood open-sourced his C# **EternityII_Solver** (the code behind the 468) in September 2020, having first asked for a standard pieces file so his repo would not ship copyrighted data ([msg 10037](https://groups.io/g/eternity2/message/10037), [msg 10034](https://groups.io/g/eternity2/message/10034)). Bucas had it running under Mono within hours ([msg 10038](https://groups.io/g/eternity2/message/10038)), rewrote it in C for roughly double the speed ([msg 10065](https://groups.io/g/eternity2/message/10065)), and published the generator behind the port as **libblackwood** (Python that emits fast C) at github.com/jfbucas/libblackwood ([msg 10078](https://groups.io/g/eternity2/message/10078)). When the original repo quietly went private, a newcomer's "Where is the software you all use?" got it re-published: "It is the exact code used to find a 470" ([msg 10161](https://groups.io/g/eternity2/message/10161)). The port, the original and the viewer are the stack behind every record since 2020; the [Blackwood solver page](/research/lab/experiments/joshua-blackwood/solver) covers the algorithm itself. The rest of the modern shelf: mtmidgee's **E2Play**, an old VB manual-play board recoded in C# and open-sourced from Australian lockdown, "not a solver (in any way shape or form)" ([msg 10208](https://groups.io/g/eternity2/message/10208)); David Barr's **solveforscore**, a Python score-maximiser published in his GitHub repo, which produced a hintless 462 ([msg 11088](https://groups.io/g/eternity2/message/11088), [msg 11101](https://groups.io/g/eternity2/message/11101)); jwortmann's **Eternity2Puzzles.jl**, a Julia package extending the complexity theory with invalid joins and a slip array ([msg 11603](https://groups.io/g/eternity2/message/11603)); and Michal Dobrogost's **eii-puzzles** (github.com/michal-dobrogost/eii-puzzles), a well-tested puzzle generator with a header-only C parsing library, generating 5-hint instances à la the original ([msg 11752](https://groups.io/g/eternity2/message/11752)). ## The conventions layer The formats outlived most of the tools, and they are what a newcomer actually needs to know. **e2pieces.txt / e2hints.txt.** The piece-file format was set by eternity2.net's BOINC client (a distributed solver needs a standard input, [msg 10952](https://groups.io/g/eternity2/message/10952)), and was consciously written down as the community standard in December 2007, with John Morrison posting explicit format descriptions ([msg 3571](https://groups.io/g/eternity2/message/3571), [msg 3572](https://groups.io/g/eternity2/message/3572)). Fifteen years of drift followed: when Vasily V. surveyed every `e2pieces.txt` he could find on GitHub in 2023, his verdict was "it's a mess!". He found inconsistent numberings, palettes and at least one bad file that had been recommended to newcomers ([msg 11033](https://groups.io/g/eternity2/message/11033)). The format-confusion thread just before it had already produced the reference piece list in the de-facto standard numbering that newcomers are pointed to today ([msg 10970](https://groups.io/g/eternity2/message/10970)), verified checksum-correct in the survey's follow-up ([msg 11034](https://groups.io/g/eternity2/message/11034)). The numbering conventions themselves are launch-week decisions: edge types numbered from the booklet, agreed before the puzzle was two weeks old ([msg 983](https://groups.io/g/eternity2/message/983)); a 2009 proposal to renumber the patterns "universally" was declined precisely because de-facto standards already existed ([msg 6804](https://groups.io/g/eternity2/message/6804)). **CRC-16 checksums.** In the contest years, when the norm was not to redistribute the piece set, the community verified transcriptions instead: publish CRC-16 checksums per 8-piece block and compare. Members converged on identical CRCs within a day of launch ([msg 1063](https://groups.io/g/eternity2/message/1063), [msg 1073](https://groups.io/g/eternity2/message/1073)); checksum utilities (Checksum-v4.txt, ChecksumCalc.zip) settled into the Files section as the standard answer to "is my piece file right?" ([msg 7591](https://groups.io/g/eternity2/message/7591)), and the protocol was extended to the clue puzzles in 2009 ([msg 6769](https://groups.io/g/eternity2/message/6769)). **The board-in-a-URL format.** Since 2019, a board *is* an e2.bucas.name URL: width, height, piece list and edges in the fragment, rendered client-side, nothing sent to any server ([msg 9955](https://groups.io/g/eternity2/message/9955)). It is the format records are announced in, verified in, and archived in: today's lingua franca, the way `e2pieces.txt` was in 2008. This site is one more branch of that lineage: its [viewer](/viewer) reads the same URL format, and the community boards it bundles are catalogued in [the notable boards](/research/community/boards). ## The census | Tool | Author | Born | Status | Source | | --- | --- | --- | --- | --- | | E2-like puzzle generator (C++) | Brendan Owen | 2007-01 | group Files (members) | [41](https://groups.io/g/eternity2/message/41) | | Benchmark corpus + generator | Sergio "Zerjillo" Alonso | 2007-05 | group Files (members) | [201](https://groups.io/g/eternity2/message/201) | | eternity2.net (BOINC) + R&D solver | Dave Clark | 2007-07 | closed 2007-12; files archived | [756](https://groups.io/g/eternity2/message/756), [3716](https://groups.io/g/eternity2/message/3716) | | Public C++ solver (squaro.fr) | Marc Lebel | 2007-08 | current status unknown | [1704](https://groups.io/g/eternity2/message/1704) | | e2walker (fill-path explorer) | Philippe Coustaux | 2007-08 | group Files (members) | [2313](https://groups.io/g/eternity2/message/2313), [7056](https://groups.io/g/eternity2/message/7056) | | Photo-based HTML visualiser | Henk van der Griendt | 2007-09 | personal; never distributed | [2499](https://groups.io/g/eternity2/message/2499) | | EPiecesV2.ps (PostScript renderer) | Ignacio Ruiz de Conejo | 2007-09 | group Files (members) | [2616](https://groups.io/g/eternity2/message/2616) | | Manual Placement Program | eii4me | 2007-12 | group Files (members) | [3541](https://groups.io/g/eternity2/message/3541) | | Eternity II Editor | Yannick Kirschhoffer | 2008-02 | SourceForge; used as late as 2023 | [4544](https://groups.io/g/eternity2/message/4544), [11074](https://groups.io/g/eternity2/message/11074) | | E2_Manual | trans.spam (Thomas) | 2008-07 | SourceForge (2009) | [5686](https://groups.io/g/eternity2/message/5686), [6765](https://groups.io/g/eternity2/message/6765) | | eii (distributed solver + decoder) | Louis Verhaard | 2008-09 | shortestpath.se/eii; fingerboys.se dead | [5940](https://groups.io/g/eternity2/message/5940), [7439](https://groups.io/g/eternity2/message/7439) | | E2Generator.jar | okifinoki (Benjamin) | 2008-10 | group Files (members) | [6036](https://groups.io/g/eternity2/message/6036) | | WhichWayToGo.jar | okifinoki (Benjamin) | 2009-03 | group Files (members) | [6572](https://groups.io/g/eternity2/message/6572) | | C++ constraint solver | Markus Zajc | 2009-05 | group Files (members) | [6748](https://groups.io/g/eternity2/message/6748) | | Java backtracker (hapl.net) | Martin Hapl | 2009-07 | hapl.net; current status unknown | [6794](https://groups.io/g/eternity2/message/6794) | | E2Lab (editor + solver) | Fred ("Eternity Blogger") | 2009-10 | author's blog; current status unknown | [7071](https://groups.io/g/eternity2/message/7071) | | Eternity II Java Toolbox | doc_s_smith (Dietmar Wolz) | 2010-06 | group Files (members) | [7755](https://groups.io/g/eternity2/message/7755) | | Edge Match Puzzles (iPhone) | Dan Hansen | 2011-07 | App Store release; status unknown | [8943](https://groups.io/g/eternity2/message/8943) | | Scan-order visualizer | Juraj Pivovarov | 2012-01 | group Files (members) | [9013](https://groups.io/g/eternity2/message/9013) | | complex_theory.pdf | Peter McGavin | 2013-07 | group Files (members) | [9188](https://groups.io/g/eternity2/message/9188) | | OpenCL/CPU solvers, solveforscore | David Barr | 2015-04 | GitHub (david3x3x3/eternity2) | [9367](https://groups.io/g/eternity2/message/9367), [11088](https://groups.io/g/eternity2/message/11088) | | Browser solver (16x16tetravex.xyz) | Guillaume L. | 2015-09 | current status unknown | [9449](https://groups.io/g/eternity2/message/9449) | | e2.bucas.name (board viewer) | Jef Bucas | 2019-11 | live | [9955](https://groups.io/g/eternity2/message/9955) | | EternityII_Solver | Joshua Blackwood | 2020-09 | GitHub (public again since 2021) | [10037](https://groups.io/g/eternity2/message/10037), [10161](https://groups.io/g/eternity2/message/10161) | | libblackwood (C port generator) | Jef Bucas | 2020-11 | GitHub (jfbucas/libblackwood) | [10078](https://groups.io/g/eternity2/message/10078) | | E2Play (manual-play board) | mtmidgee | 2021-08 | open-sourced | [10208](https://groups.io/g/eternity2/message/10208) | | Eternity2Puzzles.jl | jwortmann | 2025-08 | GitHub | [11603](https://groups.io/g/eternity2/message/11603) | | eii-puzzles (generator + C library) | Michal Dobrogost | 2026-01 | GitHub (michal-dobrogost/eii-puzzles) | [11752](https://groups.io/g/eternity2/message/11752) | Where a status says "group Files (members)", the artifact survived the 2019 Yahoo-to-groups.io migration ([msg 9934](https://groups.io/g/eternity2/message/9934)) and is accessible to [group members](https://groups.io/g/eternity2). The benchmark *suites* that travelled through these tools (Txibilis's, Geoff's, Benoist's, Owen's 9×9s and 10×10s) have [their own page](/research/build/benchmarks). ## Related - [The community's benchmarks](https://eternity2.dev/research/build/benchmarks) — How a community forbidden from sharing the pieces built a shared test culture anyway: derived-count verification protocols, the Txibilis and beginner suites, node-count duels, full enumerations, and the one benchmark that is still standing open today. - [The hunt, a history (part I: 2000–2009)](https://eternity2.dev/research/community/hunt) — The community's story, from a mailing list founded seven years before the puzzle existed to the $10,000 scrutiny prize won under a borrowed name, with every event sourced to its original message. Part I of a growing chronicle. - [The notable boards](https://eternity2.dev/research/community/boards) — The famous Eternity II boards, treated as first-class citizens: Verhaard's prize-winning 467, the Blackwood record line to 470, the strict five-clue record to 464, and this project's own boards: who found each one, when, and what makes it structurally interesting. Every bundled board opens in the viewer.