P91 · Packing and covering · Classic

L's in a square

VERIFIED CONSTRUCTIONVERIFIED CONSTRUCTION
n = 6Current record · open

Pack n L-trominoes (three unit cells) into a square. Contact is allowed; interiors cannot overlap. Minimise the container square side.

Formal definition

  • ContainerThe editor and certificate normalise the container to the unit square [0,1]², while public scores are reported in the literature's unit-cell L-tromino scale. Boundary contact is allowed.
  • SubmissionSubmit {radius, placements:[{x,y,turn,quarter},…]}, with x, y, and turn written as decimal strings of at most nine places. Here radius is the unit-cell side of each L-tromino inside the unit-square container, so the container side length is 1/radius. The coordinates x, y specify the centre of the piece's 2 × 2 bounding box; quarter is an integer in 0–3 specifying an exact multiple of 90° applied before the rational rotation turn = tan(θ/2). Coordinates and turn must lie in [−4, 4], with 0 < radius ≤ 4.
  • ConstraintsExactly n congruent L-trominoes lie wholly inside the container with pairwise disjoint interiors. Pieces may rotate independently by arbitrary angles.
  • PrecisionInput decimals are parsed as exact rationals, with zero floating-point tolerance in feasibility checks.
  • ObjectiveContainer square side = 1/r (where r is the tromino's cell side inside the unit square), where smaller is better. Pages, leaderboards, and literature records share this unit with automatic conversion.

Getting a feel for it

Literature targets and coordinate certificates

Literature targets are converted at their published precision, while nine-decimal coordinate certificates are stored and displayed alongside the source values.

Source
ONE LEADERBOARD PER n

Current best solutions by n

Each parameter n is an independently scored sub-problem. Select any card to inspect the current record construction or submit a stronger solution.

Discussion (4) ↓
n1
CURRENT RECORD2
Proven optimum
Answer sourceTrivial.
Solution methodPublished reference construction
n2
CURRENT RECORD3.000000004Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n3
CURRENT RECORD3.621320356best known [3.621, 3.622)
Matches the best known
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Sol
n4
CURRENT RECORD4Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n5
CURRENT RECORD4Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n6
CURRENT RECORD4.949747491best known [4.949, 4.95)
Matches the best known
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Sol
n7
CURRENT RECORD5Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n8
CURRENT RECORD5Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n9
CURRENT RECORD5.819010039best known [5.81901, 5.81902)
Matches the best known
Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra
n10
CURRENT RECORD6.000000025Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n11
CURRENT RECORD6.000000025Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n12
CURRENT RECORD6
Proven optimum
Answer sourceTrivial.
Solution methodPublished reference construction
n13
CURRENT RECORD6.828427144best known [6.828, 6.829)
Matches the best known
Record holdercondor
Solution methodAI · OpenAI: GPT-6.1 Sol
n14
CURRENT RECORD7.000000043Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n15
CURRENT RECORD7.000000043Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n16
CURRENT RECORD7.000000043Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n17
CURRENT RECORD7.747547108best known [7.747, 7.748)
Matches the best known
Record holder玄月
Solution methodHuman
n18
CURRENT RECORD7.91421366best known [7.914, 7.915)
Matches the best known
Record holderAnonymous
Solution methodHuman
n19
CURRENT RECORD8Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n20
CURRENT RECORD8Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n21
CURRENT RECORD8Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n22
CURRENT RECORD8.656909044best known [8.656, 8.657)
Matches the best known
Record holder邱仲普
Solution methodAI · OpenAI: GPT-5.6 Sol
n23
CURRENT RECORD8.914213735best known [8.914, 8.915)
Matches the best known
Record holderAnonymous
Solution methodHuman
n24
CURRENT RECORD9.00000001Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n25
CURRENT RECORD9.00000001Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n26
CURRENT RECORD9.00000001Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n27
CURRENT RECORD9
Proven optimum
Answer sourceTrivial.
Solution methodPublished reference construction
n28
CURRENT RECORD9.794501371best known [9.79450, 9.79451)
Matches the best known
Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra
n29
CURRENT RECORD9.931980633best known [9.93198, 9.93199)
Matches the best known
Record holder今天
Solution methodAI · DeepSeek: DeepSeek V4.1 Flash
n30
CURRENT RECORD10Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n31
CURRENT RECORD10Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n32
CURRENT RECORD10Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n33
CURRENT RECORD10Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n34
CURRENT RECORD10.656854404best known 5 + 4√2
Hard
Record holderNUE_13
Solution methodAI · DeepSeek: DeepSeek V4 Flash 0423
n35
CURRENT RECORD10.863961185best known 9(1 + √2)/2
Hard
Record holderNUE_13
Solution methodAI · DeepSeek: DeepSeek V4 Flash 0423
n36
CURRENT RECORD11.000000111Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n37
CURRENT RECORD11.000000111Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n38
CURRENT RECORD11.000000111Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n39
CURRENT RECORD11.000000111Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction
n40
CURRENT RECORD11.000000111Source value unresolved
Hard
Answer sourceTrivial.
Solution methodPublished reference construction

Data and citation

All sub-problems in this family — authoritative scores, proof status, coordinates, and sources — are published at the stable URL below under CC BY 4.0. Because scores update as records fall, please cite the file's generatedAt timestamp.

GET https://minmaxarena.com/data/ells-in-square.json

Cite the frozen 2026-10 edition: live records change, whereas a frozen edition stays fixed and reproducible.

GET https://minmaxarena.com/data/editions/2026-10/ells-in-square.json
BibTeX (click to copy)
@misc{minmaxarena-ells-in-square-2026-10,
  title  = {{L's in a square} (P91)},
  author = {{MinMax Arena}},
  year   = {2026},
  note   = {Machine-verified records, 2026-10 edition},
  url    = {https://minmaxarena.com/data/editions/2026-10/ells-in-square.json},
  license = {CC BY 4.0}
}
DISCUSSION

Discussion

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