P83 · Packing and covering · Classic · Hard

Equilateral triangles in a square · n = 35

Pack n unit-side equilateral triangles into a square. Contact is allowed; interiors cannot overlap. Minimise the container square side.

Instancen = 35
ObjectiveMinimize container square side

Record comparison

container square side · Lower is better
RecordValue / intervalAuthor / holderSource
External best known[4.14123, 4.14124)35. Found by Jake LoydErich Friedman ↗
Site recordNo player record yet——

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-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 square side = 1/(2 sin(π/3) r), where smaller is better. Pages, leaderboards, and literature records share this unit with automatic conversion.
Open full editor ↗

Layout shown: starter layout

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 current arrangement for Equilateral triangles in a square n = 35
LAYOUT & HISTORY

Starter layout

Inspect the layout, solver notes and record history.

Challenge this record ↗Submit a proof / idea ↓Share a proof or bound argument in the discussion board. Accepted contributions earn proof points.
ANSWER FORMAT

How to write your answer

the unit square [0,1]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.

Starter answer

{
  "placements": [
    {
      "turn": "0.267949192",
      "x": "0.154841169",
      "y": "0.930292475"
    },
    {
      "turn": "0.267949192",
      "x": "0.396315121",
      "y": "0.930292475"
    },
    {
      "turn": "0.267949192",
      "x": "0.637789073",
      "y": "0.930292475"
    },
    {
      "turn": "0.267949192",
      "x": "0.879263024",
      "y": "0.930292475"
    },
    {
      "turn": "-0.267949192",
      "x": "0.758526048",
      "y": "0.860584949"
    },
    {
      "turn": "-0.267949192",
      "x": "0.275578145",
      "y": "0.860584949"
    },
    {
      "turn": "-0.267949192",
      "x": "0.517052097",
      "y": "0.860584949"
    },
    {
      "turn": "0.000000000",
      "x": "0.069707525",
      "y": "0.759538039"
    },
    {
      "turn": "0.577350269",
      "x": "0.930292475",
      "y": "0.739847973"
    },
    {
      "turn": "0.267949192",
      "x": "0.458128363",
      "y": "0.721169898"
    },
    {
      "turn": "0.267949192",
      "x": "0.699602315",
      "y": "0.721169898"
    },
    {
      "turn": "-0.267949192",
      "x": "0.578865339",
      "y": "0.651462373"
    },
    {
      "turn": "0.577350269",
      "x": "0.144634433",
      "y": "0.641814474"
    },
    {
      "turn": "-0.004563660",
      "x": "0.285148563",
      "y": "0.641173216"
    },
    {
      "turn": "0.000000000",
      "x": "0.860584949",
      "y": "0.619110997"
    },
    {
      "turn": "0.008523613",
      "x": "0.072063567",
      "y": "0.519089240"
    },
    {
      "turn": "-0.011106254",
      "x": "0.459367497",
      "y": "0.499445024"
    },
    {
      "turn": "0.562636279",
      "x": "0.319918220",
      "y": "0.499452760"
    },
    {
      "turn": "0.477929053",
      "x": "0.699172003",
      "y": "0.506745197"
    },
    {
      "turn": "-0.577350269",
      "x": "0.930292475",
      "y": "0.498374022"
    },
    {
      "turn": "-0.000000000",
      "x": "0.860584949",
      "y": "0.377637046"
    },
    {
      "turn": "-0.577350269",
      "x": "0.139415051",
      "y": "0.364450894"
    },
    {
      "turn": "-0.002992458",
      "x": "0.280824786",
      "y": "0.356904426"
    },
    {
      "turn": "0.267949192",
      "x": "0.576987821",
      "y": "0.348537627"
    },
    {
      "turn": "-0.267949192",
      "x": "0.697724796",
      "y": "0.278830102"
    },
    {
      "turn": "-0.267949192",
      "x": "0.456250845",
      "y": "0.278830102"
    },
    {
      "turn": "0.577350269",
      "x": "0.930292475",
      "y": "0.256900070"
    },
    {
      "turn": "0.000000000",
      "x": "0.069707525",
      "y": "0.243713918"
    },
    {
      "turn": "0.267949192",
      "x": "0.269945591",
      "y": "0.139415051"
    },
    {
      "turn": "0.267949192",
      "x": "0.511419542",
      "y": "0.139415051"
    },
    {
      "turn": "0.267949192",
      "x": "0.752893494",
      "y": "0.139415051"
    },
    {
      "turn": "-0.267949192",
      "x": "0.149208615",
      "y": "0.069707525"
    },
    {
      "turn": "-0.267949192",
      "x": "0.390682566",
      "y": "0.069707525"
    },
    {
      "turn": "-0.267949192",
      "x": "0.632156518",
      "y": "0.069707525"
    },
    {
      "turn": "-0.267949192",
      "x": "0.873630470",
      "y": "0.069707525"
    }
  ],
  "radius": "0.139415049"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 35,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0.267949192",
      "x": "0.154841169",
      "y": "0.930292475"
    },
    {
      "turn": "0.267949192",
      "x": "0.396315121",
      "y": "0.930292475"
    },
    {
      "turn": "0.267949192",
      "x": "0.637789073",
      "y": "0.930292475"
    },
    {
      "turn": "0.267949192",
      "x": "0.879263024",
      "y": "0.930292475"
    },
    {
      "turn": "-0.267949192",
      "x": "0.758526048",
      "y": "0.860584949"
    },
    {
      "turn": "-0.267949192",
      "x": "0.275578145",
      "y": "0.860584949"
    },
    {
      "turn": "-0.267949192",
      "x": "0.517052097",
      "y": "0.860584949"
    },
    {
      "turn": "0.000000000",
      "x": "0.069707525",
      "y": "0.759538039"
    },
    {
      "turn": "0.577350269",
      "x": "0.930292475",
      "y": "0.739847973"
    },
    {
      "turn": "0.267949192",
      "x": "0.458128363",
      "y": "0.721169898"
    },
    {
      "turn": "0.267949192",
      "x": "0.699602315",
      "y": "0.721169898"
    },
    {
      "turn": "-0.267949192",
      "x": "0.578865339",
      "y": "0.651462373"
    },
    {
      "turn": "0.577350269",
      "x": "0.144634433",
      "y": "0.641814474"
    },
    {
      "turn": "-0.004563660",
      "x": "0.285148563",
      "y": "0.641173216"
    },
    {
      "turn": "0.000000000",
      "x": "0.860584949",
      "y": "0.619110997"
    },
    {
      "turn": "0.008523613",
      "x": "0.072063567",
      "y": "0.519089240"
    },
    {
      "turn": "-0.011106254",
      "x": "0.459367497",
      "y": "0.499445024"
    },
    {
      "turn": "0.562636279",
      "x": "0.319918220",
      "y": "0.499452760"
    },
    {
      "turn": "0.477929053",
      "x": "0.699172003",
      "y": "0.506745197"
    },
    {
      "turn": "-0.577350269",
      "x": "0.930292475",
      "y": "0.498374022"
    },
    {
      "turn": "-0.000000000",
      "x": "0.860584949",
      "y": "0.377637046"
    },
    {
      "turn": "-0.577350269",
      "x": "0.139415051",
      "y": "0.364450894"
    },
    {
      "turn": "-0.002992458",
      "x": "0.280824786",
      "y": "0.356904426"
    },
    {
      "turn": "0.267949192",
      "x": "0.576987821",
      "y": "0.348537627"
    },
    {
      "turn": "-0.267949192",
      "x": "0.697724796",
      "y": "0.278830102"
    },
    {
      "turn": "-0.267949192",
      "x": "0.456250845",
      "y": "0.278830102"
    },
    {
      "turn": "0.577350269",
      "x": "0.930292475",
      "y": "0.256900070"
    },
    {
      "turn": "0.000000000",
      "x": "0.069707525",
      "y": "0.243713918"
    },
    {
      "turn": "0.267949192",
      "x": "0.269945591",
      "y": "0.139415051"
    },
    {
      "turn": "0.267949192",
      "x": "0.511419542",
      "y": "0.139415051"
    },
    {
      "turn": "0.267949192",
      "x": "0.752893494",
      "y": "0.139415051"
    },
    {
      "turn": "-0.267949192",
      "x": "0.149208615",
      "y": "0.069707525"
    },
    {
      "turn": "-0.267949192",
      "x": "0.390682566",
      "y": "0.069707525"
    },
    {
      "turn": "-0.267949192",
      "x": "0.632156518",
      "y": "0.069707525"
    },
    {
      "turn": "-0.267949192",
      "x": "0.873630470",
      "y": "0.069707525"
    }
  ],
  "radius": "0.139415049"
}

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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