# Research
> The open research wiki of the Eternity II community: why the puzzle is so hard, everything you need to build a solver, and the researchers' open notebooks: records, methods, experiments and dead ends, all sourced and reproducible.
- Canonical page (with interactive figures/demos): https://eternity2.dev/research/
- Updated: 2026-07-21
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> **Note**
>
> This wiki is a work in progress: the site is young and slowly absorbing years of community research. If something you know is missing, the mailing list below is the right place to say so.
This wiki is for the people who want to actually solve it. Everyone who has
attacked Eternity II took one of nine roads, from modelling why it resists,
through pruning the search and building boards up, to throwing hardware at the wall.
Pick the road you care about; each opens onto everything the wiki knows about
it, drawn from the theory, the solver-building guides, and the lab notebook
alike.
## New here? Start with these
Five pages, in order, take you from never having heard of the puzzle to picking
a target of your own:
1. **[Why it resists](/research/why)**: the structural walls that make Eternity
II hard, so you know what you are up against.
2. **[The state of the art](/research/records)**: who holds the best board and
how far it is from a full solution.
3. **[Get the code running](/research/build/toolkit)**: the starter kit that
already scores, generates and benchmarks, so you write only the solver.
4. **[Pick a target](/research/open-problems)**: the open frontier, one row per
angle still worth a run, tagged by how approachable it is.
5. **[Contribute](/research/contribute)**: how to write up what you find, credited
to you, beside the rest.
> **[Interactive: RootsDiagram]** Rendered on the canonical page (link above); not shown in this markdown export.
Prefer to browse by reading mode rather than by method? The wiki splits four
ways:
- [Why it's hard](/research/why) — The design that was tuned to resist cleverness, and the structural walls (rigidity, entropy, forbidden patterns) that explain the gap between the best known board and a full solution.
- [Build a solver](/research/build) — Validation data, the literature ranked by usefulness, the methods behind the records, the dead ends, and how to run the code yourself.
- [The lab](/research/lab) — The open notebook: structural findings and the named search experiments built to attack the puzzle, each credited to its author and reproducible from source.
- [History & community](/research/community) — The record and the people behind it: two decades told as a story, the record boards themselves, the record-holders and theorists, and the papers.
Or browse by method instead: the nine roads in the left rail are each a hub
gathering every article on that theme.
## The reference shelf
The lookups and the frontier you will reach for again and again while reading
or building:
- [Reference](/research/reference) — The exact counts (pieces, colours, edges) to check your own edge-matching and constraint code against.
- [Glossary](/research/glossary) — Every term the wiki leans on, defined once: community jargon, the loaded computer-science words, and the notation the boards are written in.
- [Open problems](/research/open-problems) — The open frontier on one board: every angle still worth a run, the wall it attacks, and where the last attempt stopped.
The story of the puzzle, its records and the people who chased them now live
together under [History & community](/research/community).
## Community infrastructure
The research conversation lives in a few long-standing places:
- [e2.bucas.name board viewer](https://e2.bucas.name) — Jef Bucas's GPL viewer; its URL format is the community's lingua franca (and this site speaks it natively).
- [Eternity II Discord](https://discord.gg/Ny5xs3q8w) — An active server where puzzlers share their runs, records and code, in real time.
- [groups.io/g/eternity2](https://groups.io/g/eternity2) — The active mailing list: records, techniques, and 15+ years of accumulated folklore.
## Pages in this section
- [Build a solver](https://eternity2.dev/research/build) — The practitioner's corner of the wiki: validation data to check your code against, the literature ranked by usefulness, the record timeline and the methods behind it, the dead ends, and how to run the code yourself.
- [History & community](https://eternity2.dev/research/community) — The record and the people behind it: two decades of Eternity II told as a story, the record boards themselves, the record-holders and theorists, the academic literature, and how to add your own work to the wiki.
- [Contribute your research](https://eternity2.dev/research/contribute) — This wiki is the community's research home, and there is room in it for your work. Three ways to get it published, from a mailing-list post to a pull request, plus the small set of house rules that keep every page trustworthy.
- [History: the big steps](https://eternity2.dev/research/history) — The Eternity II story at a glance, from the mailing list founded in 2000 to the 470 record that still stands. A scannable timeline of the turning points, each linking into the full two-part history and the message where it happened.
- [The lab](https://eternity2.dev/research/lab) — The wiki's open notebook: structural findings and named search experiments, each credited to the researcher who ran it and reproducible from source. One corner of the community's wider research.
- [Open problems](https://eternity2.dev/research/open-problems) — The open frontier of Eternity II in one place: every angle still worth a run, the wall it attacks, what has been tried and where it stopped, and whether it is a newcomer-tractable target or a hard, well-mapped one.
- [Papers](https://eternity2.dev/research/papers) — The academic literature on Eternity II and edge-matching puzzles, drawn from the project's research notes and the community reading list, and ranked by how useful each paper actually is if your goal is to write a solver.
- [Who's who of E2 research](https://eternity2.dev/research/people) — Two decades of Eternity II research were done by named people on a mailing list. This page is the gallery: who they are, what each of them contributed, and where to read it in their own words. A thank-you as much as an index.
- [Records & solvers](https://eternity2.dev/research/records) — Eternity II has never been solved, but fifteen years of community effort have pushed the best board to 470/480. Who holds what, how they did it, and why some headline "480" boards are not actually the real puzzle.
- [Reference numbers](https://eternity2.dev/research/reference) — Exact counts of how many valid ways a small block can be filled at a given position of the official Eternity II board, under increasingly constrained rules: known-good numbers to check your solver's edge-matching and constraint code against.
- [Why it's hard](https://eternity2.dev/research/why) — Eternity II is not accidentally difficult. It was designed to resist cleverness, and the measurable structural walls (rigidity, entropy, forbidden patterns) explain why no search, however clever, has reached the end.