P83 · Packing and covering · Classic · Hard

Equilateral triangles in a square · n = 29

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

Instancen = 29
ObjectiveMinimize container square side

Record comparison

container square side · Lower is better
RecordValue / intervalAuthor / holderSource
External best known[3.81711, 3.81712)29. 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 = 29
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": "0.250345188",
      "y": "0.924373441"
    },
    {
      "turn": "0.542850509",
      "x": "0.463733195",
      "y": "0.873161848"
    },
    {
      "turn": "-0.010932812",
      "x": "0.618876826",
      "y": "0.867388842"
    },
    {
      "turn": "0.562864621",
      "x": "0.921527702",
      "y": "0.870695691"
    },
    {
      "turn": "0.000000000",
      "x": "0.075626559",
      "y": "0.813763777"
    },
    {
      "turn": "-0.026267222",
      "x": "0.381334231",
      "y": "0.746323696"
    },
    {
      "turn": "-0.010932812",
      "x": "0.843055405",
      "y": "0.741391381"
    },
    {
      "turn": "0.562864621",
      "x": "0.691621494",
      "y": "0.734777684"
    },
    {
      "turn": "0.577350269",
      "x": "0.151253119",
      "y": "0.682774734"
    },
    {
      "turn": "0.562864621",
      "x": "0.462036286",
      "y": "0.613538524"
    },
    {
      "turn": "0.565324785",
      "x": "0.922010889",
      "y": "0.611658015"
    },
    {
      "turn": "-0.010932812",
      "x": "0.613149196",
      "y": "0.605473375"
    },
    {
      "turn": "-0.000000000",
      "x": "0.075626559",
      "y": "0.551785691"
    },
    {
      "turn": "-0.000000000",
      "x": "0.302506238",
      "y": "0.530097815"
    },
    {
      "turn": "-0.009066323",
      "x": "0.844021779",
      "y": "0.482061701"
    },
    {
      "turn": "0.562864621",
      "x": "0.692150726",
      "y": "0.476294457"
    },
    {
      "turn": "0.577350269",
      "x": "0.151253119",
      "y": "0.420796647"
    },
    {
      "turn": "-0.577350269",
      "x": "0.924373441",
      "y": "0.351072658"
    },
    {
      "turn": "0.267949192",
      "x": "0.452526310",
      "y": "0.378132797"
    },
    {
      "turn": "-0.267949192",
      "x": "0.321537266",
      "y": "0.302506238"
    },
    {
      "turn": "-0.267949192",
      "x": "0.583515353",
      "y": "0.302506238"
    },
    {
      "turn": "0.000000000",
      "x": "0.075626559",
      "y": "0.289807604"
    },
    {
      "turn": "0.062056907",
      "x": "0.789550705",
      "y": "0.236229974"
    },
    {
      "turn": "-0.431496614",
      "x": "0.896229548",
      "y": "0.110041807"
    },
    {
      "turn": "0.267949192",
      "x": "0.262587119",
      "y": "0.151253119"
    },
    {
      "turn": "0.267949192",
      "x": "0.524566011",
      "y": "0.151253119"
    },
    {
      "turn": "-0.267949194",
      "x": "0.130989056",
      "y": "0.076680480"
    },
    {
      "turn": "-0.267949192",
      "x": "0.393576567",
      "y": "0.075626559"
    },
    {
      "turn": "-0.267949192",
      "x": "0.655555539",
      "y": "0.075626559"
    }
  ],
  "radius": "0.151253117"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 29,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0.267949192",
      "x": "0.250345188",
      "y": "0.924373441"
    },
    {
      "turn": "0.542850509",
      "x": "0.463733195",
      "y": "0.873161848"
    },
    {
      "turn": "-0.010932812",
      "x": "0.618876826",
      "y": "0.867388842"
    },
    {
      "turn": "0.562864621",
      "x": "0.921527702",
      "y": "0.870695691"
    },
    {
      "turn": "0.000000000",
      "x": "0.075626559",
      "y": "0.813763777"
    },
    {
      "turn": "-0.026267222",
      "x": "0.381334231",
      "y": "0.746323696"
    },
    {
      "turn": "-0.010932812",
      "x": "0.843055405",
      "y": "0.741391381"
    },
    {
      "turn": "0.562864621",
      "x": "0.691621494",
      "y": "0.734777684"
    },
    {
      "turn": "0.577350269",
      "x": "0.151253119",
      "y": "0.682774734"
    },
    {
      "turn": "0.562864621",
      "x": "0.462036286",
      "y": "0.613538524"
    },
    {
      "turn": "0.565324785",
      "x": "0.922010889",
      "y": "0.611658015"
    },
    {
      "turn": "-0.010932812",
      "x": "0.613149196",
      "y": "0.605473375"
    },
    {
      "turn": "-0.000000000",
      "x": "0.075626559",
      "y": "0.551785691"
    },
    {
      "turn": "-0.000000000",
      "x": "0.302506238",
      "y": "0.530097815"
    },
    {
      "turn": "-0.009066323",
      "x": "0.844021779",
      "y": "0.482061701"
    },
    {
      "turn": "0.562864621",
      "x": "0.692150726",
      "y": "0.476294457"
    },
    {
      "turn": "0.577350269",
      "x": "0.151253119",
      "y": "0.420796647"
    },
    {
      "turn": "-0.577350269",
      "x": "0.924373441",
      "y": "0.351072658"
    },
    {
      "turn": "0.267949192",
      "x": "0.452526310",
      "y": "0.378132797"
    },
    {
      "turn": "-0.267949192",
      "x": "0.321537266",
      "y": "0.302506238"
    },
    {
      "turn": "-0.267949192",
      "x": "0.583515353",
      "y": "0.302506238"
    },
    {
      "turn": "0.000000000",
      "x": "0.075626559",
      "y": "0.289807604"
    },
    {
      "turn": "0.062056907",
      "x": "0.789550705",
      "y": "0.236229974"
    },
    {
      "turn": "-0.431496614",
      "x": "0.896229548",
      "y": "0.110041807"
    },
    {
      "turn": "0.267949192",
      "x": "0.262587119",
      "y": "0.151253119"
    },
    {
      "turn": "0.267949192",
      "x": "0.524566011",
      "y": "0.151253119"
    },
    {
      "turn": "-0.267949194",
      "x": "0.130989056",
      "y": "0.076680480"
    },
    {
      "turn": "-0.267949192",
      "x": "0.393576567",
      "y": "0.075626559"
    },
    {
      "turn": "-0.267949192",
      "x": "0.655555539",
      "y": "0.075626559"
    }
  ],
  "radius": "0.151253117"
}

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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