P83 · Packing and covering · Classic · Hard

Equilateral triangles in a square · n = 24

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

Instancen = 24
ObjectiveMinimize container square side

Record comparison

container square side · Lower is better
RecordValue / intervalAuthor / holderSource
External best known[3.4678, 3.46781)24. Found by Thomas SchadtErich 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.
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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 Equilateral triangles in a square n = 24
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": "0.281018884",
      "x": "0.312505754",
      "y": "0.913275885"
    },
    {
      "turn": "0.295339675",
      "x": "0.594865460",
      "y": "0.909548339"
    },
    {
      "turn": "-0.000284210",
      "x": "0.817802366",
      "y": "0.855769383"
    },
    {
      "turn": "0.000534035",
      "x": "0.083398230",
      "y": "0.855905670"
    },
    {
      "turn": "-0.240928761",
      "x": "0.455090864",
      "y": "0.819096678"
    },
    {
      "turn": "0.577350269",
      "x": "0.916755720",
      "y": "0.720561079"
    },
    {
      "turn": "-0.576638442",
      "x": "0.166796461",
      "y": "0.711811341"
    },
    {
      "turn": "-0.576638442",
      "x": "0.651271102",
      "y": "0.674850351"
    },
    {
      "turn": "0.000534035",
      "x": "0.333380850",
      "y": "0.622178103"
    },
    {
      "turn": "0.000534035",
      "x": "0.833203539",
      "y": "0.576377757"
    },
    {
      "turn": "0.000534035",
      "x": "0.083398230",
      "y": "0.567716573"
    },
    {
      "turn": "0.000534035",
      "x": "0.583220919",
      "y": "0.521916227"
    },
    {
      "turn": "-0.576638442",
      "x": "0.416779081",
      "y": "0.478083773"
    },
    {
      "turn": "-0.576638442",
      "x": "0.916601770",
      "y": "0.432283427"
    },
    {
      "turn": "-0.576638442",
      "x": "0.166796461",
      "y": "0.423622243"
    },
    {
      "turn": "-0.576638442",
      "x": "0.666619150",
      "y": "0.377821897"
    },
    {
      "turn": "0.000534035",
      "x": "0.348728898",
      "y": "0.325149649"
    },
    {
      "turn": "0.000534035",
      "x": "0.833203539",
      "y": "0.288188659"
    },
    {
      "turn": "0.000000000",
      "x": "0.083244280",
      "y": "0.279438921"
    },
    {
      "turn": "0.295339675",
      "x": "0.544909136",
      "y": "0.180903322"
    },
    {
      "turn": "0.576971385",
      "x": "0.182197634",
      "y": "0.144230617"
    },
    {
      "turn": "-0.576638442",
      "x": "0.916601770",
      "y": "0.144094330"
    },
    {
      "turn": "-0.240928761",
      "x": "0.405134540",
      "y": "0.090451661"
    },
    {
      "turn": "-0.254964355",
      "x": "0.687494246",
      "y": "0.086724115"
    }
  ],
  "radius": "0.166488559"
}
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": "0.281018884",
      "x": "0.312505754",
      "y": "0.913275885"
    },
    {
      "turn": "0.295339675",
      "x": "0.594865460",
      "y": "0.909548339"
    },
    {
      "turn": "-0.000284210",
      "x": "0.817802366",
      "y": "0.855769383"
    },
    {
      "turn": "0.000534035",
      "x": "0.083398230",
      "y": "0.855905670"
    },
    {
      "turn": "-0.240928761",
      "x": "0.455090864",
      "y": "0.819096678"
    },
    {
      "turn": "0.577350269",
      "x": "0.916755720",
      "y": "0.720561079"
    },
    {
      "turn": "-0.576638442",
      "x": "0.166796461",
      "y": "0.711811341"
    },
    {
      "turn": "-0.576638442",
      "x": "0.651271102",
      "y": "0.674850351"
    },
    {
      "turn": "0.000534035",
      "x": "0.333380850",
      "y": "0.622178103"
    },
    {
      "turn": "0.000534035",
      "x": "0.833203539",
      "y": "0.576377757"
    },
    {
      "turn": "0.000534035",
      "x": "0.083398230",
      "y": "0.567716573"
    },
    {
      "turn": "0.000534035",
      "x": "0.583220919",
      "y": "0.521916227"
    },
    {
      "turn": "-0.576638442",
      "x": "0.416779081",
      "y": "0.478083773"
    },
    {
      "turn": "-0.576638442",
      "x": "0.916601770",
      "y": "0.432283427"
    },
    {
      "turn": "-0.576638442",
      "x": "0.166796461",
      "y": "0.423622243"
    },
    {
      "turn": "-0.576638442",
      "x": "0.666619150",
      "y": "0.377821897"
    },
    {
      "turn": "0.000534035",
      "x": "0.348728898",
      "y": "0.325149649"
    },
    {
      "turn": "0.000534035",
      "x": "0.833203539",
      "y": "0.288188659"
    },
    {
      "turn": "0.000000000",
      "x": "0.083244280",
      "y": "0.279438921"
    },
    {
      "turn": "0.295339675",
      "x": "0.544909136",
      "y": "0.180903322"
    },
    {
      "turn": "0.576971385",
      "x": "0.182197634",
      "y": "0.144230617"
    },
    {
      "turn": "-0.576638442",
      "x": "0.916601770",
      "y": "0.144094330"
    },
    {
      "turn": "-0.240928761",
      "x": "0.405134540",
      "y": "0.090451661"
    },
    {
      "turn": "-0.254964355",
      "x": "0.687494246",
      "y": "0.086724115"
    }
  ],
  "radius": "0.166488559"
}

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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