P85 · Packing and covering · Classic · Hard

Squares in an equilateral triangle · n = 37

Pack n unit squares into an equilateral triangle container with boundary contact allowed and disjoint interiors, minimising the side length of the container triangle.

Instancen = 37
ObjectiveMinimize container triangle side

Record comparison

container triangle side · Lower is better
RecordValue / intervalAuthor / holderSource
External best known[10.15299, 10.153)Gianluca CostantinoErich Friedman ↗
Site record10.154700681zzzcyRecord details ↓

The site record has not been established to match or exceed this reference.

Formal definition

  • ContainerThe editor and certificate normalise the container to the equilateral triangle with vertices (0,0), (1,0), and (1/2,√3/2), while public scores are reported in the literature's unit-piece scale. Boundary contact is allowed.
  • SubmissionSubmit {radius, placements:[{x,y,turn},…]}, with each value written as a decimal string of at most nine places. Here x, y are centre coordinates; circles require turn = 0 and polygons use 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. Polygons may rotate independently by arbitrary angles.
  • PrecisionInput decimals are parsed as exact rationals and regular-polygon vertices are defined algebraically, with zero floating-point tolerance in feasibility checks.
  • ObjectiveContainer triangle side = 1/(2 sin(π/4) r), 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 Squares in an equilateral triangle n = 37, 10.154700681
LAYOUT & HISTORY

Record details

Inspect the layout, solver notes and record history.

Record holderzzzcy
Solution methodAI · OpenAI: GPT-6 Astra
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 (16 changes)
  1. zzzcyAI · OpenAI: GPT-6 Astra
    10.196988928→10.154700681
  2. 今天Human
    10.197870262→10.196988928
  3. 10.199682675→10.197870262
  4. NUE_13Human
    10.199757268→10.199682675
  5. 10.205165462→10.199757268
  6. 玄月Human
    10.205490233→10.205165462
  7. 10.215915976→10.205490233
  8. 10.228118725→10.215915976
  9. 10.238250109→10.228118725
  10. NUE_13Human
    10.251523839→10.238250109
  11. 10.287407136→10.251523839
  12. NUE_13Human
    10.996648554→10.287407136
  13. 11.211251296→10.996648554
  14. 11.844416633→11.211251296
  15. 14.480990809→11.844416633
  16. 迪AI · OpenAI: GPT-5.6 Sol
    29.168155016→14.480990809
ANSWER FORMAT

How to write your answer

the equilateral triangle with vertices (0,0), (1,0), (1/2,√3/2)

Submit {radius, placements:[{x,y,turn},…]}, with each value written as a decimal string of at most nine places. Here x, y are centre coordinates; circles require turn = 0 and polygons use turn = tan(θ/2). Coordinates and turn must lie in [−4, 4], with 0 < radius ≤ 4.

The current leader's answer

{
  "placements": [
    {
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      "x": "0.833080772",
      "y": "0.149836700"
    },
    {
      "turn": "-0.414213562",
      "x": "0.500000000",
      "y": "0.049270942"
    },
    {
      "turn": "-0.414213562",
      "x": "0.401523438",
      "y": "0.049297691"
    },
    {
      "turn": "-0.274301057",
      "x": "0.678187542",
      "y": "0.259785701"
    },
    {
      "turn": "-0.000152567",
      "x": "0.499417315",
      "y": "0.744317188"
    },
    {
      "turn": "0.414213562",
      "x": "0.303046875",
      "y": "0.050249402"
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    {
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      "x": "0.696953125",
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    },
    {
      "turn": "0.008349536",
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      "y": "0.279875611"
    },
    {
      "turn": "0.004589437",
      "x": "0.440764644",
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    {
      "turn": "-0.003915883",
      "x": "0.551445312",
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    {
      "turn": "0.004027813",
      "x": "0.510959633",
      "y": "0.168182124"
    },
    {
      "turn": "0.022855201",
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      "y": "0.446055568"
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    {
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    },
    {
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      "x": "0.204570313",
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    {
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      "x": "0.795429687",
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    {
      "turn": "0.104545640",
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      "y": "0.376954923"
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    {
      "turn": "0.133211224",
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    {
      "turn": "0.112935015",
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    },
    {
      "turn": "0.000417387",
      "x": "0.610309587",
      "y": "0.357254573"
    },
    {
      "turn": "-0.126314395",
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    {
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    {
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      "x": "0.441067020",
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    {
      "turn": "-0.131824702",
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    {
      "turn": "-0.131628999",
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    {
      "turn": "0.400372884",
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      "x": "0.264944651",
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    {
      "turn": "0.002972310",
      "x": "0.557317177",
      "y": "0.260879371"
    },
    {
      "turn": "-0.002823761",
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    },
    {
      "turn": "0.412743290",
      "x": "0.163106726",
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    {
      "turn": "0.409415038",
      "x": "0.261905800",
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    {
      "turn": "-0.000890731",
      "x": "0.435584530",
      "y": "0.633663580"
    },
    {
      "turn": "0.002724417",
      "x": "0.492435894",
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    {
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      "y": "0.149857478"
    },
    {
      "turn": "0.413283780",
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      "y": "0.147852010"
    }
  ],
  "radius": "0.069633444"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 37,
  "sides": 5
}

The current leader's answer

{
  "placements": [
    {
      "turn": "0.403481513",
      "x": "0.833080772",
      "y": "0.149836700"
    },
    {
      "turn": "-0.414213562",
      "x": "0.500000000",
      "y": "0.049270942"
    },
    {
      "turn": "-0.414213562",
      "x": "0.401523438",
      "y": "0.049297691"
    },
    {
      "turn": "-0.274301057",
      "x": "0.678187542",
      "y": "0.259785701"
    },
    {
      "turn": "-0.000152567",
      "x": "0.499417315",
      "y": "0.744317188"
    },
    {
      "turn": "0.414213562",
      "x": "0.303046875",
      "y": "0.050249402"
    },
    {
      "turn": "0.414213562",
      "x": "0.696953125",
      "y": "0.049307986"
    },
    {
      "turn": "0.008349536",
      "x": "0.344362562",
      "y": "0.279875611"
    },
    {
      "turn": "0.004589437",
      "x": "0.440764644",
      "y": "0.237332705"
    },
    {
      "turn": "-0.003915883",
      "x": "0.551445312",
      "y": "0.656795342"
    },
    {
      "turn": "0.004027813",
      "x": "0.510959633",
      "y": "0.168182124"
    },
    {
      "turn": "0.022855201",
      "x": "0.556737113",
      "y": "0.446055568"
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    {
      "turn": "0.130863055",
      "x": "0.314522430",
      "y": "0.446102934"
    },
    {
      "turn": "-0.414213562",
      "x": "0.204570313",
      "y": "0.049415397"
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    {
      "turn": "0.112935015",
      "x": "0.366765525",
      "y": "0.531651958"
    },
    {
      "turn": "0.000417387",
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    {
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    {
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    {
      "turn": "0.134293038",
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    {
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    {
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    {
      "turn": "0.002724417",
      "x": "0.492435894",
      "y": "0.335403816"
    },
    {
      "turn": "0.414194857",
      "x": "0.631568876",
      "y": "0.149857478"
    },
    {
      "turn": "0.413283780",
      "x": "0.733612281",
      "y": "0.147852010"
    }
  ],
  "radius": "0.069633444"
}

Submit {radius, placements:[{x,y,turn},…]}, with each value written as a decimal string of at most nine places. Here x, y are centre coordinates; circles require turn = 0 and polygons use 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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