P83 · Packing and covering · Classic · Hard

Equilateral triangles in a square · n = 32

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

Instancen = 32
ObjectiveMinimize container square side

Record comparison

container square side · Lower is better
RecordValue / intervalAuthor / holderSource
External best known[3.9788, 3.97881)32. 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 = 32
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": "0.273403183",
      "y": "0.927446691"
    },
    {
      "turn": "0.267949192",
      "x": "0.725944708",
      "y": "0.927446691"
    },
    {
      "turn": "0.005249269",
      "x": "0.073868583",
      "y": "0.875102591"
    },
    {
      "turn": "0.568642410",
      "x": "0.925805363",
      "y": "0.875296006"
    },
    {
      "turn": "0.267949192",
      "x": "0.499673946",
      "y": "0.884039297"
    },
    {
      "turn": "-0.267949192",
      "x": "0.374007929",
      "y": "0.811485989"
    },
    {
      "turn": "-0.267949192",
      "x": "0.625339962",
      "y": "0.811485989"
    },
    {
      "turn": "-0.570372392",
      "x": "0.147737167",
      "y": "0.750205183"
    },
    {
      "turn": "-0.006555613",
      "x": "0.851610725",
      "y": "0.750592012"
    },
    {
      "turn": "0.001903605",
      "x": "0.294145047",
      "y": "0.629126025"
    },
    {
      "turn": "0.000000000",
      "x": "0.072553309",
      "y": "0.624539166"
    },
    {
      "turn": "0.267949192",
      "x": "0.501838684",
      "y": "0.666379372"
    },
    {
      "turn": "-0.568866686",
      "x": "0.704887299",
      "y": "0.623505006"
    },
    {
      "turn": "0.568642410",
      "x": "0.925805363",
      "y": "0.625830845"
    },
    {
      "turn": "-0.574814916",
      "x": "0.367176265",
      "y": "0.503737144"
    },
    {
      "turn": "0.573887845",
      "x": "0.148399784",
      "y": "0.500020836"
    },
    {
      "turn": "-0.002600717",
      "x": "0.851600216",
      "y": "0.499979164"
    },
    {
      "turn": "0.001903605",
      "x": "0.632823735",
      "y": "0.496262856"
    },
    {
      "turn": "0.006386147",
      "x": "0.295112701",
      "y": "0.376494994"
    },
    {
      "turn": "-0.006555613",
      "x": "0.074194637",
      "y": "0.374169155"
    },
    {
      "turn": "-0.574814916",
      "x": "0.705854953",
      "y": "0.370873975"
    },
    {
      "turn": "-0.577350269",
      "x": "0.927446691",
      "y": "0.375460834"
    },
    {
      "turn": "-0.267949192",
      "x": "0.498161316",
      "y": "0.333620628"
    },
    {
      "turn": "0.568642410",
      "x": "0.148389275",
      "y": "0.249407988"
    },
    {
      "turn": "0.005249269",
      "x": "0.852262833",
      "y": "0.249794817"
    },
    {
      "turn": "0.267949192",
      "x": "0.374660038",
      "y": "0.188514011"
    },
    {
      "turn": "0.267949192",
      "x": "0.625992071",
      "y": "0.188514011"
    },
    {
      "turn": "-0.267949192",
      "x": "0.500326054",
      "y": "0.115960703"
    },
    {
      "turn": "-0.006555613",
      "x": "0.074194637",
      "y": "0.124703994"
    },
    {
      "turn": "-0.570372392",
      "x": "0.926131417",
      "y": "0.124897409"
    },
    {
      "turn": "-0.267949192",
      "x": "0.274055292",
      "y": "0.072553309"
    },
    {
      "turn": "-0.267949192",
      "x": "0.726596817",
      "y": "0.072553309"
    }
  ],
  "radius": "0.145106616"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 32,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0.267949192",
      "x": "0.273403183",
      "y": "0.927446691"
    },
    {
      "turn": "0.267949192",
      "x": "0.725944708",
      "y": "0.927446691"
    },
    {
      "turn": "0.005249269",
      "x": "0.073868583",
      "y": "0.875102591"
    },
    {
      "turn": "0.568642410",
      "x": "0.925805363",
      "y": "0.875296006"
    },
    {
      "turn": "0.267949192",
      "x": "0.499673946",
      "y": "0.884039297"
    },
    {
      "turn": "-0.267949192",
      "x": "0.374007929",
      "y": "0.811485989"
    },
    {
      "turn": "-0.267949192",
      "x": "0.625339962",
      "y": "0.811485989"
    },
    {
      "turn": "-0.570372392",
      "x": "0.147737167",
      "y": "0.750205183"
    },
    {
      "turn": "-0.006555613",
      "x": "0.851610725",
      "y": "0.750592012"
    },
    {
      "turn": "0.001903605",
      "x": "0.294145047",
      "y": "0.629126025"
    },
    {
      "turn": "0.000000000",
      "x": "0.072553309",
      "y": "0.624539166"
    },
    {
      "turn": "0.267949192",
      "x": "0.501838684",
      "y": "0.666379372"
    },
    {
      "turn": "-0.568866686",
      "x": "0.704887299",
      "y": "0.623505006"
    },
    {
      "turn": "0.568642410",
      "x": "0.925805363",
      "y": "0.625830845"
    },
    {
      "turn": "-0.574814916",
      "x": "0.367176265",
      "y": "0.503737144"
    },
    {
      "turn": "0.573887845",
      "x": "0.148399784",
      "y": "0.500020836"
    },
    {
      "turn": "-0.002600717",
      "x": "0.851600216",
      "y": "0.499979164"
    },
    {
      "turn": "0.001903605",
      "x": "0.632823735",
      "y": "0.496262856"
    },
    {
      "turn": "0.006386147",
      "x": "0.295112701",
      "y": "0.376494994"
    },
    {
      "turn": "-0.006555613",
      "x": "0.074194637",
      "y": "0.374169155"
    },
    {
      "turn": "-0.574814916",
      "x": "0.705854953",
      "y": "0.370873975"
    },
    {
      "turn": "-0.577350269",
      "x": "0.927446691",
      "y": "0.375460834"
    },
    {
      "turn": "-0.267949192",
      "x": "0.498161316",
      "y": "0.333620628"
    },
    {
      "turn": "0.568642410",
      "x": "0.148389275",
      "y": "0.249407988"
    },
    {
      "turn": "0.005249269",
      "x": "0.852262833",
      "y": "0.249794817"
    },
    {
      "turn": "0.267949192",
      "x": "0.374660038",
      "y": "0.188514011"
    },
    {
      "turn": "0.267949192",
      "x": "0.625992071",
      "y": "0.188514011"
    },
    {
      "turn": "-0.267949192",
      "x": "0.500326054",
      "y": "0.115960703"
    },
    {
      "turn": "-0.006555613",
      "x": "0.074194637",
      "y": "0.124703994"
    },
    {
      "turn": "-0.570372392",
      "x": "0.926131417",
      "y": "0.124897409"
    },
    {
      "turn": "-0.267949192",
      "x": "0.274055292",
      "y": "0.072553309"
    },
    {
      "turn": "-0.267949192",
      "x": "0.726596817",
      "y": "0.072553309"
    }
  ],
  "radius": "0.145106616"
}

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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