P85 · Packing and covering · Classic · Hard

Squares in an equilateral triangle · n = 36

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 = 36
ObjectiveMinimize container triangle side

Record comparison

container triangle side · Lower is better
RecordValue / intervalAuthor / holderSource
External best known[9.773, 9.774)Erich FriedmanErich Friedman ↗
Site recordNo player record yet——

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.
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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 Squares in an equilateral triangle n = 36
LAYOUT & HISTORY

Starter layout

Inspect the layout, solver notes and record history.

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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.

Starter answer

{
  "placements": [
    {
      "turn": "0.131652498",
      "x": "0.386871425",
      "y": "0.158493649"
    },
    {
      "turn": "0.131652498",
      "x": "0.268725395",
      "y": "0.158493649"
    },
    {
      "turn": "0.131652498",
      "x": "0.099420634",
      "y": "0.069884127"
    },
    {
      "turn": "-0.131652498",
      "x": "0.392665082",
      "y": "0.540347619"
    },
    {
      "turn": "-0.131652498",
      "x": "0.451738097",
      "y": "0.642665082"
    },
    {
      "turn": "-0.131652498",
      "x": "0.510811112",
      "y": "0.744982545"
    },
    {
      "turn": "-0.131652498",
      "x": "0.561969844",
      "y": "0.656373023"
    },
    {
      "turn": "-0.131652498",
      "x": "0.613128575",
      "y": "0.567763501"
    },
    {
      "turn": "-0.131652498",
      "x": "0.502896829",
      "y": "0.554055560"
    },
    {
      "turn": "-0.131652498",
      "x": "0.664287307",
      "y": "0.479153979"
    },
    {
      "turn": "-0.131652498",
      "x": "0.554055560",
      "y": "0.465446038"
    },
    {
      "turn": "-0.131652498",
      "x": "0.443823814",
      "y": "0.451738097"
    },
    {
      "turn": "-0.131652498",
      "x": "0.715446038",
      "y": "0.390544457"
    },
    {
      "turn": "-0.131652498",
      "x": "0.605214292",
      "y": "0.376836516"
    },
    {
      "turn": "-0.131652498",
      "x": "0.494982545",
      "y": "0.363128575"
    },
    {
      "turn": "0.131652498",
      "x": "0.304055560",
      "y": "0.424322216"
    },
    {
      "turn": "-0.414213562",
      "x": "0.771622224",
      "y": "0.255793657"
    },
    {
      "turn": "-0.414213562",
      "x": "0.669304761",
      "y": "0.255793657"
    },
    {
      "turn": "-0.414213562",
      "x": "0.566987298",
      "y": "0.255793657"
    },
    {
      "turn": "0.131652498",
      "x": "0.371042858",
      "y": "0.335712693"
    },
    {
      "turn": "0.131652498",
      "x": "0.252896829",
      "y": "0.335712693"
    },
    {
      "turn": "-0.414213562",
      "x": "0.830695239",
      "y": "0.153476194"
    },
    {
      "turn": "-0.414213562",
      "x": "0.728377776",
      "y": "0.153476194"
    },
    {
      "turn": "-0.414213562",
      "x": "0.626060313",
      "y": "0.153476194"
    },
    {
      "turn": "-0.414213562",
      "x": "0.523742850",
      "y": "0.153476194"
    },
    {
      "turn": "0.131652498",
      "x": "0.438030156",
      "y": "0.247103171"
    },
    {
      "turn": "0.131652498",
      "x": "0.319884127",
      "y": "0.247103171"
    },
    {
      "turn": "0.131652498",
      "x": "0.201738097",
      "y": "0.247103171"
    },
    {
      "turn": "-0.414213562",
      "x": "0.889768254",
      "y": "0.051158731"
    },
    {
      "turn": "-0.414213562",
      "x": "0.787450791",
      "y": "0.051158731"
    },
    {
      "turn": "-0.414213562",
      "x": "0.685133328",
      "y": "0.051158731"
    },
    {
      "turn": "-0.414213562",
      "x": "0.582815865",
      "y": "0.051158731"
    },
    {
      "turn": "-0.414213562",
      "x": "0.480498402",
      "y": "0.051158731"
    },
    {
      "turn": "0.131652498",
      "x": "0.335712693",
      "y": "0.069884127"
    },
    {
      "turn": "0.131652498",
      "x": "0.217566664",
      "y": "0.069884127"
    },
    {
      "turn": "0.131652498",
      "x": "0.150579366",
      "y": "0.158493649"
    }
  ],
  "radius": "0.072349371"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 36,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0.131652498",
      "x": "0.386871425",
      "y": "0.158493649"
    },
    {
      "turn": "0.131652498",
      "x": "0.268725395",
      "y": "0.158493649"
    },
    {
      "turn": "0.131652498",
      "x": "0.099420634",
      "y": "0.069884127"
    },
    {
      "turn": "-0.131652498",
      "x": "0.392665082",
      "y": "0.540347619"
    },
    {
      "turn": "-0.131652498",
      "x": "0.451738097",
      "y": "0.642665082"
    },
    {
      "turn": "-0.131652498",
      "x": "0.510811112",
      "y": "0.744982545"
    },
    {
      "turn": "-0.131652498",
      "x": "0.561969844",
      "y": "0.656373023"
    },
    {
      "turn": "-0.131652498",
      "x": "0.613128575",
      "y": "0.567763501"
    },
    {
      "turn": "-0.131652498",
      "x": "0.502896829",
      "y": "0.554055560"
    },
    {
      "turn": "-0.131652498",
      "x": "0.664287307",
      "y": "0.479153979"
    },
    {
      "turn": "-0.131652498",
      "x": "0.554055560",
      "y": "0.465446038"
    },
    {
      "turn": "-0.131652498",
      "x": "0.443823814",
      "y": "0.451738097"
    },
    {
      "turn": "-0.131652498",
      "x": "0.715446038",
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    {
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      "x": "0.605214292",
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    },
    {
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      "x": "0.494982545",
      "y": "0.363128575"
    },
    {
      "turn": "0.131652498",
      "x": "0.304055560",
      "y": "0.424322216"
    },
    {
      "turn": "-0.414213562",
      "x": "0.771622224",
      "y": "0.255793657"
    },
    {
      "turn": "-0.414213562",
      "x": "0.669304761",
      "y": "0.255793657"
    },
    {
      "turn": "-0.414213562",
      "x": "0.566987298",
      "y": "0.255793657"
    },
    {
      "turn": "0.131652498",
      "x": "0.371042858",
      "y": "0.335712693"
    },
    {
      "turn": "0.131652498",
      "x": "0.252896829",
      "y": "0.335712693"
    },
    {
      "turn": "-0.414213562",
      "x": "0.830695239",
      "y": "0.153476194"
    },
    {
      "turn": "-0.414213562",
      "x": "0.728377776",
      "y": "0.153476194"
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    {
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    {
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    },
    {
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    },
    {
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      "x": "0.319884127",
      "y": "0.247103171"
    },
    {
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      "x": "0.201738097",
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    },
    {
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      "x": "0.889768254",
      "y": "0.051158731"
    },
    {
      "turn": "-0.414213562",
      "x": "0.787450791",
      "y": "0.051158731"
    },
    {
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      "x": "0.685133328",
      "y": "0.051158731"
    },
    {
      "turn": "-0.414213562",
      "x": "0.582815865",
      "y": "0.051158731"
    },
    {
      "turn": "-0.414213562",
      "x": "0.480498402",
      "y": "0.051158731"
    },
    {
      "turn": "0.131652498",
      "x": "0.335712693",
      "y": "0.069884127"
    },
    {
      "turn": "0.131652498",
      "x": "0.217566664",
      "y": "0.069884127"
    },
    {
      "turn": "0.131652498",
      "x": "0.150579366",
      "y": "0.158493649"
    }
  ],
  "radius": "0.072349371"
}

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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