P91 · Packing and covering · Classic · Hard

L's in a square · n = 17

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

Instancen = 17
ObjectiveMinimize container square side

Record comparison

container square side · Lower is better
RecordValue / intervalAuthor / holderSource
External best known[7.747, 7.748)Maurizio MorandiErich Friedman ↗
Site record7.747547108玄月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 = 17, 7.747547108
LAYOUT & HISTORY

Record details

Inspect the layout, solver notes and record history.

Record holder玄月
Solution methodHuman
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 (1 changes)
  1. 玄月Human
    7.747547168→7.747547108
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": 2,
      "turn": "-0.000000172",
      "x": "0.131803914",
      "y": "0.516292497"
    },
    {
      "turn": "0.405462072",
      "x": "0.703249322",
      "y": "0.275769455"
    },
    {
      "quarter": 2,
      "turn": "-0.401579635",
      "x": "0.612669365",
      "y": "0.554181814"
    },
    {
      "turn": "-0.000000133",
      "x": "0.130265469",
      "y": "0.387219375"
    },
    {
      "quarter": 2,
      "turn": "0.414213562",
      "x": "0.306390333",
      "y": "0.736634052"
    },
    {
      "quarter": 3,
      "turn": "-0.407623071",
      "x": "0.796137275",
      "y": "0.370658168"
    },
    {
      "quarter": 2,
      "turn": "0.000000000",
      "x": "0.483707553",
      "y": "0.870926887"
    },
    {
      "turn": "0.000000000",
      "x": "0.741853775",
      "y": "0.870483827"
    },
    {
      "quarter": 2,
      "turn": "-0.006879541",
      "x": "0.869162191",
      "y": "0.610573142"
    },
    {
      "quarter": 2,
      "turn": "-0.000000085",
      "x": "0.390110872",
      "y": "0.516292469"
    },
    {
      "turn": "-0.000000081",
      "x": "0.390099211",
      "y": "0.387219356"
    },
    {
      "quarter": 2,
      "turn": "-0.000000011",
      "x": "0.262830685",
      "y": "0.129073118"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.129073113",
      "y": "0.870926887"
    },
    {
      "quarter": 2,
      "turn": "0.000000000",
      "x": "0.870926887",
      "y": "0.870490688"
    },
    {
      "turn": "0.000000005",
      "x": "0.133738134",
      "y": "0.129073114"
    },
    {
      "turn": "0.000000000",
      "x": "0.523057898",
      "y": "0.129073113"
    },
    {
      "quarter": 1,
      "turn": "-0.001725289",
      "x": "0.870465245",
      "y": "0.129542974"
    }
  ],
  "radius": "0.129073110"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 17,
  "sides": 5
}

The current leader's answer

{
  "placements": [
    {
      "quarter": 2,
      "turn": "-0.000000172",
      "x": "0.131803914",
      "y": "0.516292497"
    },
    {
      "turn": "0.405462072",
      "x": "0.703249322",
      "y": "0.275769455"
    },
    {
      "quarter": 2,
      "turn": "-0.401579635",
      "x": "0.612669365",
      "y": "0.554181814"
    },
    {
      "turn": "-0.000000133",
      "x": "0.130265469",
      "y": "0.387219375"
    },
    {
      "quarter": 2,
      "turn": "0.414213562",
      "x": "0.306390333",
      "y": "0.736634052"
    },
    {
      "quarter": 3,
      "turn": "-0.407623071",
      "x": "0.796137275",
      "y": "0.370658168"
    },
    {
      "quarter": 2,
      "turn": "0.000000000",
      "x": "0.483707553",
      "y": "0.870926887"
    },
    {
      "turn": "0.000000000",
      "x": "0.741853775",
      "y": "0.870483827"
    },
    {
      "quarter": 2,
      "turn": "-0.006879541",
      "x": "0.869162191",
      "y": "0.610573142"
    },
    {
      "quarter": 2,
      "turn": "-0.000000085",
      "x": "0.390110872",
      "y": "0.516292469"
    },
    {
      "turn": "-0.000000081",
      "x": "0.390099211",
      "y": "0.387219356"
    },
    {
      "quarter": 2,
      "turn": "-0.000000011",
      "x": "0.262830685",
      "y": "0.129073118"
    },
    {
      "quarter": 3,
      "turn": "0.000000000",
      "x": "0.129073113",
      "y": "0.870926887"
    },
    {
      "quarter": 2,
      "turn": "0.000000000",
      "x": "0.870926887",
      "y": "0.870490688"
    },
    {
      "turn": "0.000000005",
      "x": "0.133738134",
      "y": "0.129073114"
    },
    {
      "turn": "0.000000000",
      "x": "0.523057898",
      "y": "0.129073113"
    },
    {
      "quarter": 1,
      "turn": "-0.001725289",
      "x": "0.870465245",
      "y": "0.129542974"
    }
  ],
  "radius": "0.129073110"
}

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

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