P91 · Packing and covering · Classic · Hard

L's in a square · n = 29

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

Instancen = 29
ObjectiveMinimize container square side

Record comparison

container square side · Lower is better
RecordValue / intervalAuthor / holderSource
External best known[9.93198, 9.93199)Yanis GomesErich Friedman ↗
Site record9.931980633今天Record details ↓

Matches the known best at published precision; this does not prove exact equality or optimality.

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.
Open full editor ↗

Layout shown: site record

VERIFIED CONSTRUCTIONVERIFIED CONSTRUCTION

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
The record-holding arrangement for L's in a square n = 29, 9.931980633
LAYOUT & HISTORY

Record details

Inspect the layout, solver notes and record history.

Record holder今天
Solution methodAI · DeepSeek: DeepSeek V4.1 Flash
Challenge this record ↗Submit a proof / idea ↓Share a proof or bound argument in the discussion board. Accepted contributions earn proof points.
Record holder's solver noteNo solver note yet (expand)+

The record holder has not shared a solver note yet.

Record history (2 changes)
  1. 今天AI · DeepSeek: DeepSeek V4.1 Flash
    9.932195386→9.931980633
  2. NUE_13Human
    10→9.932195386
ANSWER FORMAT

How to write your answer

the unit square [0,1]²

Submit {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.

The current leader's answer

{
  "placements": [
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.402739413",
      "y": "0.395890881"
    },
    {
      "turn": "0.000000000",
      "x": "0.697945440",
      "y": "0.100684853"
    },
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.899315147",
      "y": "0.100684853"
    },
    {
      "quarter": 2,
      "turn": "-0.414213562",
      "x": "0.574619208",
      "y": "0.421803066"
    },
    {
      "turn": "0.414213562",
      "x": "0.716250212",
      "y": "0.564951832"
    },
    {
      "turn": "0.414213562",
      "x": "0.367525182",
      "y": "0.222790593"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.100684853",
      "y": "0.899315147"
    },
    {
      "turn": "-0.414213562",
      "x": "0.928805058",
      "y": "0.779566641"
    },
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.899315147",
      "y": "0.503424266"
    },
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.201369706",
      "y": "0.395890881"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.402739413",
      "y": "0.899315147"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.100684853",
      "y": "0.194521175"
    },
    {
      "quarter": 3,
      "turn": "-0.414213562",
      "x": "0.786571012",
      "y": "0.637020917"
    },
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.697945440",
      "y": "0.302054560"
    },
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.798630294",
      "y": "0.201369706"
    },
    {
      "quarter": 3,
      "turn": "-0.414213562",
      "x": "0.227237521",
      "y": "0.074816166"
    },
    {
      "quarter": 2,
      "turn": "0.000000000",
      "x": "0.302054560",
      "y": "0.496575734"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.503424266",
      "y": "0.798630294"
    },
    {
      "quarter": 2,
      "turn": "0.000000000",
      "x": "0.402739413",
      "y": "0.597260587"
    },
    {
      "quarter": 2,
      "turn": "0.000000000",
      "x": "0.899315147",
      "y": "0.302054560"
    },
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.496575734",
      "y": "0.100684853"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.302054560",
      "y": "0.697945440"
    },
    {
      "turn": "0.000000000",
      "x": "0.100684853",
      "y": "0.597260587"
    },
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.201369706",
      "y": "0.899315147"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.100684853",
      "y": "0.395890881"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.604109119",
      "y": "0.697945440"
    },
    {
      "quarter": 2,
      "turn": "0.000000000",
      "x": "0.100684853",
      "y": "0.697945440"
    },
    {
      "quarter": 2,
      "turn": "0.000000000",
      "x": "0.604109119",
      "y": "0.899315147"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.805478825",
      "y": "0.899315147"
    }
  ],
  "radius": "0.100684852"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 29,
  "sides": 5
}

The current leader's answer

{
  "placements": [
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.402739413",
      "y": "0.395890881"
    },
    {
      "turn": "0.000000000",
      "x": "0.697945440",
      "y": "0.100684853"
    },
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.899315147",
      "y": "0.100684853"
    },
    {
      "quarter": 2,
      "turn": "-0.414213562",
      "x": "0.574619208",
      "y": "0.421803066"
    },
    {
      "turn": "0.414213562",
      "x": "0.716250212",
      "y": "0.564951832"
    },
    {
      "turn": "0.414213562",
      "x": "0.367525182",
      "y": "0.222790593"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.100684853",
      "y": "0.899315147"
    },
    {
      "turn": "-0.414213562",
      "x": "0.928805058",
      "y": "0.779566641"
    },
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.899315147",
      "y": "0.503424266"
    },
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.201369706",
      "y": "0.395890881"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.402739413",
      "y": "0.899315147"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.100684853",
      "y": "0.194521175"
    },
    {
      "quarter": 3,
      "turn": "-0.414213562",
      "x": "0.786571012",
      "y": "0.637020917"
    },
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.697945440",
      "y": "0.302054560"
    },
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.798630294",
      "y": "0.201369706"
    },
    {
      "quarter": 3,
      "turn": "-0.414213562",
      "x": "0.227237521",
      "y": "0.074816166"
    },
    {
      "quarter": 2,
      "turn": "0.000000000",
      "x": "0.302054560",
      "y": "0.496575734"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.503424266",
      "y": "0.798630294"
    },
    {
      "quarter": 2,
      "turn": "0.000000000",
      "x": "0.402739413",
      "y": "0.597260587"
    },
    {
      "quarter": 2,
      "turn": "0.000000000",
      "x": "0.899315147",
      "y": "0.302054560"
    },
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.496575734",
      "y": "0.100684853"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.302054560",
      "y": "0.697945440"
    },
    {
      "turn": "0.000000000",
      "x": "0.100684853",
      "y": "0.597260587"
    },
    {
      "quarter": 1,
      "turn": "0.000000000",
      "x": "0.201369706",
      "y": "0.899315147"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.100684853",
      "y": "0.395890881"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.604109119",
      "y": "0.697945440"
    },
    {
      "quarter": 2,
      "turn": "0.000000000",
      "x": "0.100684853",
      "y": "0.697945440"
    },
    {
      "quarter": 2,
      "turn": "0.000000000",
      "x": "0.604109119",
      "y": "0.899315147"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.805478825",
      "y": "0.899315147"
    }
  ],
  "radius": "0.100684852"
}

Submit {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. · Verifier v1.0.0

DISCUSSION

Discussion

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