# Build boards up

> Building a high-scoring board from an empty grid instead of digging with backtracking: beam search keeps the best partial boards alive and grows them cell by cell. The workhorse behind this project's from-scratch builders, and a clean illustration of why breadth alone stalls in the deep interior.

- Canonical page (with interactive figures/demos): https://eternity2.dev/research/build/construct/
- Updated: 2026-07-13

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Building a high-scoring board from an empty grid instead of digging with backtracking: beam search keeps the best partial boards alive and grows them cell by cell. The workhorse behind this project's from-scratch builders, and a clean illustration of why breadth alone stalls in the deep interior.

The pages below go technique by technique: what each is in a line, what it
actually reached on the real 16×16 board, where it stops, and the labs and
measurements to back it. For the whole territory at once, start with
[a map of every known approach](/research/build/approaches-map).

## Pages in this section

- [Beam search](https://eternity2.dev/research/build/construct/beam-search) — Keep the K most promising partial boards alive at once and grow them cell by cell. Beam search is the workhorse behind this project's from-scratch builders, and a clean illustration of why breadth alone stalls in the deep interior.

## Related

- [A map of every known approach](https://eternity2.dev/research/build/approaches-map) — The survey the community keeps asking for and never finds: every family of attack tried on Eternity II, what each one actually reached, where it walls out, and a link to the deep page. One organising insight runs through all of them.
- [The techniques](https://eternity2.dev/research/build/techniques) — The technique shelf: the algorithms and pruning ideas that recur in every serious Eternity II solver, each with what it is, what it costs, and what it actually bought when measured on this puzzle.