P85 · Packing and covering · Classic · Hard

Squares in an equilateral triangle · n = 24

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 = 24
ObjectiveMinimize container triangle side

Record comparison

container triangle side · Lower is better
RecordValue / intervalAuthor / holderSource
External best known[8.309, 8.31)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 = 24
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": "0.116938372",
      "y": "0.082197585"
    },
    {
      "turn": "-0.131652498",
      "x": "0.512716011",
      "y": "0.723655010"
    },
    {
      "turn": "-0.131652498",
      "x": "0.572888819",
      "y": "0.619432649"
    },
    {
      "turn": "-0.131652498",
      "x": "0.633061628",
      "y": "0.515210287"
    },
    {
      "turn": "0.131652498",
      "x": "0.417802415",
      "y": "0.603309393"
    },
    {
      "turn": "-0.131652498",
      "x": "0.693234436",
      "y": "0.410987925"
    },
    {
      "turn": "0.131652498",
      "x": "0.466506351",
      "y": "0.446975851"
    },
    {
      "turn": "0.131652498",
      "x": "0.357629606",
      "y": "0.499087032"
    },
    {
      "turn": "-0.131652498",
      "x": "0.753407245",
      "y": "0.306765564"
    },
    {
      "turn": "0.131652498",
      "x": "0.540642308",
      "y": "0.334691861"
    },
    {
      "turn": "0.131652498",
      "x": "0.406333542",
      "y": "0.342753489"
    },
    {
      "turn": "0.131652498",
      "x": "0.297456798",
      "y": "0.394864670"
    },
    {
      "turn": "-0.131652498",
      "x": "0.813580053",
      "y": "0.202543202"
    },
    {
      "turn": "0.131652498",
      "x": "0.610123883",
      "y": "0.214346244"
    },
    {
      "turn": "0.131652498",
      "x": "0.480469500",
      "y": "0.230469500"
    },
    {
      "turn": "0.131652498",
      "x": "0.346160734",
      "y": "0.238531127"
    },
    {
      "turn": "0.131652498",
      "x": "0.237283989",
      "y": "0.290642308"
    },
    {
      "turn": "-0.414213562",
      "x": "0.870345617",
      "y": "0.060172809"
    },
    {
      "turn": "-0.414213562",
      "x": "0.750000000",
      "y": "0.060172809"
    },
    {
      "turn": "-0.414213562",
      "x": "0.629654383",
      "y": "0.060172809"
    },
    {
      "turn": "-0.414213562",
      "x": "0.509308766",
      "y": "0.060172809"
    },
    {
      "turn": "-0.414213562",
      "x": "0.388963149",
      "y": "0.060172809"
    },
    {
      "turn": "-0.414213562",
      "x": "0.268617532",
      "y": "0.060172809"
    },
    {
      "turn": "0.131652498",
      "x": "0.177111181",
      "y": "0.186419947"
    }
  ],
  "radius": "0.085097201"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 24,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0.131652498",
      "x": "0.116938372",
      "y": "0.082197585"
    },
    {
      "turn": "-0.131652498",
      "x": "0.512716011",
      "y": "0.723655010"
    },
    {
      "turn": "-0.131652498",
      "x": "0.572888819",
      "y": "0.619432649"
    },
    {
      "turn": "-0.131652498",
      "x": "0.633061628",
      "y": "0.515210287"
    },
    {
      "turn": "0.131652498",
      "x": "0.417802415",
      "y": "0.603309393"
    },
    {
      "turn": "-0.131652498",
      "x": "0.693234436",
      "y": "0.410987925"
    },
    {
      "turn": "0.131652498",
      "x": "0.466506351",
      "y": "0.446975851"
    },
    {
      "turn": "0.131652498",
      "x": "0.357629606",
      "y": "0.499087032"
    },
    {
      "turn": "-0.131652498",
      "x": "0.753407245",
      "y": "0.306765564"
    },
    {
      "turn": "0.131652498",
      "x": "0.540642308",
      "y": "0.334691861"
    },
    {
      "turn": "0.131652498",
      "x": "0.406333542",
      "y": "0.342753489"
    },
    {
      "turn": "0.131652498",
      "x": "0.297456798",
      "y": "0.394864670"
    },
    {
      "turn": "-0.131652498",
      "x": "0.813580053",
      "y": "0.202543202"
    },
    {
      "turn": "0.131652498",
      "x": "0.610123883",
      "y": "0.214346244"
    },
    {
      "turn": "0.131652498",
      "x": "0.480469500",
      "y": "0.230469500"
    },
    {
      "turn": "0.131652498",
      "x": "0.346160734",
      "y": "0.238531127"
    },
    {
      "turn": "0.131652498",
      "x": "0.237283989",
      "y": "0.290642308"
    },
    {
      "turn": "-0.414213562",
      "x": "0.870345617",
      "y": "0.060172809"
    },
    {
      "turn": "-0.414213562",
      "x": "0.750000000",
      "y": "0.060172809"
    },
    {
      "turn": "-0.414213562",
      "x": "0.629654383",
      "y": "0.060172809"
    },
    {
      "turn": "-0.414213562",
      "x": "0.509308766",
      "y": "0.060172809"
    },
    {
      "turn": "-0.414213562",
      "x": "0.388963149",
      "y": "0.060172809"
    },
    {
      "turn": "-0.414213562",
      "x": "0.268617532",
      "y": "0.060172809"
    },
    {
      "turn": "0.131652498",
      "x": "0.177111181",
      "y": "0.186419947"
    }
  ],
  "radius": "0.085097201"
}

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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