P89 · Packing and covering · Classic · Hard

Tans in a square · n = 14

Pack n tans (right isosceles triangles of leg 1) into a square. Contact is allowed; interiors cannot overlap. Minimise the container square side.

Instancen = 14
ObjectiveMinimize container square side

Record comparison

container square side · Lower is better
RecordValue / intervalAuthor / holderSource
External best known[2.76246, 2.76247)Joshua Wolk2026-09Erich Friedman ↗
Site record2.762459564邱仲普Record details ↓

Numerically exceeds the published range · awaiting review.

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-leg 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 leg length of each piece inside the unit-square container, so the container side length is 1/radius. The coordinates x, y specify the centre of the piece's 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 pieces 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 piece's leg length 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 Tans in a square n = 14, 2.762459564
LAYOUT & HISTORY

Record details

Inspect the layout, solver notes and record history.

Record holder邱仲普
Solution methodAI · OpenAI: GPT-5.6 Sol
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 (4 changes)
  1. 邱仲普AI · OpenAI: GPT-5.6 Sol
    2.762459579→2.762459564
  2. 邱仲普AI · OpenAI: GPT-5.6 Sol
    2.762459587→2.762459579
  3. zzzcyAI · OpenAI: GPT-6 Astra
    2.762863488→2.762459587
  4. NUE_13Human
    2.763450004→2.762863488
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 leg length of each piece inside the unit-square container, so the container side length is 1/radius. The coordinates x, y specify the centre of the piece's 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": 3,
      "turn": "-0.000000004",
      "x": "0.180998126",
      "y": "0.819001874"
    },
    {
      "quarter": 1,
      "turn": "-0.414198588",
      "x": "0.720083859",
      "y": "0.999728682"
    },
    {
      "quarter": 1,
      "turn": "0.387734711",
      "x": "0.720948972",
      "y": "0.500266330"
    },
    {
      "quarter": 3,
      "turn": "0.414213547",
      "x": "0.999999993",
      "y": "0.255970003"
    },
    {
      "quarter": 3,
      "turn": "-0.411788443",
      "x": "0.723994492",
      "y": "0.001060664"
    },
    {
      "quarter": 3,
      "turn": "-0.062223625",
      "x": "0.204832116",
      "y": "0.483631945"
    },
    {
      "quarter": 1,
      "turn": "-0.062223623",
      "x": "0.246915483",
      "y": "0.516368043"
    },
    {
      "quarter": 1,
      "turn": "-0.028096207",
      "x": "0.265914091",
      "y": "0.190875292"
    },
    {
      "quarter": 3,
      "turn": "0.387734708",
      "x": "0.720912100",
      "y": "0.499458717"
    },
    {
      "quarter": 1,
      "turn": "0.381675506",
      "x": "0.450836215",
      "y": "0.255566198"
    },
    {
      "quarter": 1,
      "turn": "-0.062223616",
      "x": "0.249707809",
      "y": "0.842835869"
    },
    {
      "quarter": 3,
      "turn": "-0.062223626",
      "x": "0.202039806",
      "y": "0.157164116"
    },
    {
      "quarter": 3,
      "turn": "0.387734724",
      "x": "0.988326323",
      "y": "0.744296327"
    },
    {
      "quarter": 1,
      "turn": "0.387734713",
      "x": "0.452185895",
      "y": "0.744296327"
    }
  ],
  "radius": "0.361996249"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 14,
  "sides": 5
}

The current leader's answer

{
  "placements": [
    {
      "quarter": 3,
      "turn": "-0.000000004",
      "x": "0.180998126",
      "y": "0.819001874"
    },
    {
      "quarter": 1,
      "turn": "-0.414198588",
      "x": "0.720083859",
      "y": "0.999728682"
    },
    {
      "quarter": 1,
      "turn": "0.387734711",
      "x": "0.720948972",
      "y": "0.500266330"
    },
    {
      "quarter": 3,
      "turn": "0.414213547",
      "x": "0.999999993",
      "y": "0.255970003"
    },
    {
      "quarter": 3,
      "turn": "-0.411788443",
      "x": "0.723994492",
      "y": "0.001060664"
    },
    {
      "quarter": 3,
      "turn": "-0.062223625",
      "x": "0.204832116",
      "y": "0.483631945"
    },
    {
      "quarter": 1,
      "turn": "-0.062223623",
      "x": "0.246915483",
      "y": "0.516368043"
    },
    {
      "quarter": 1,
      "turn": "-0.028096207",
      "x": "0.265914091",
      "y": "0.190875292"
    },
    {
      "quarter": 3,
      "turn": "0.387734708",
      "x": "0.720912100",
      "y": "0.499458717"
    },
    {
      "quarter": 1,
      "turn": "0.381675506",
      "x": "0.450836215",
      "y": "0.255566198"
    },
    {
      "quarter": 1,
      "turn": "-0.062223616",
      "x": "0.249707809",
      "y": "0.842835869"
    },
    {
      "quarter": 3,
      "turn": "-0.062223626",
      "x": "0.202039806",
      "y": "0.157164116"
    },
    {
      "quarter": 3,
      "turn": "0.387734724",
      "x": "0.988326323",
      "y": "0.744296327"
    },
    {
      "quarter": 1,
      "turn": "0.387734713",
      "x": "0.452185895",
      "y": "0.744296327"
    }
  ],
  "radius": "0.361996249"
}

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 leg length of each piece inside the unit-square container, so the container side length is 1/radius. The coordinates x, y specify the centre of the piece's 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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