P82 · Packing and covering · Classic · Hard

Equal circles in regular polygons · m = 8 · n = 27

Pack n equal circles into the regular m-gon with centre (1,1), circumradius 1, and first vertex (2,1) so as to maximise their common radius.

Instancem = 8 · n = 27
ObjectiveMaximize circle radius

Record comparison

circle radius · Higher is better
RecordValue / intervalAuthor / holderSource
External best known[0.161395047684, 0.161395047686]Paolo AmorePackomania ↗
Site recordNo player record yet——

Formal definition

  • ContainerThe editor and certificate normalise the container to the exact regular m-gon with centre (1,1), circumradius 1, and first vertex (2,1), while public scores follow the literature convention. 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.
  • ObjectiveMaximise the circle radius r (with container circumradius fixed at 1).
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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. Pentagon and hexagon rows n = 41–100 and octagon rows n = 41–48 cite Packomania's value and author without importing its coordinates; they start from an ordinary site grid baseline.

Source
The current arrangement for Equal circles in regular polygons m = 8 · n = 27
LAYOUT & HISTORY

Starter layout

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ANSWER FORMAT

How to write your answer

the regular m-gon with centre (1,1), circumradius 1, and first vertex (2,1)

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",
      "x": "0.449874147",
      "y": "0.402562330"
    },
    {
      "turn": "0",
      "x": "0.966545494",
      "y": "0.188550051"
    },
    {
      "turn": "0",
      "x": "0.769922565",
      "y": "0.444543937"
    },
    {
      "turn": "0",
      "x": "0.303081062",
      "y": "0.690043175"
    },
    {
      "turn": "0",
      "x": "1.273623534",
      "y": "0.288031320"
    },
    {
      "turn": "0",
      "x": "0.623129480",
      "y": "0.732024781"
    },
    {
      "turn": "0",
      "x": "1.077000606",
      "y": "0.544025206"
    },
    {
      "turn": "0",
      "x": "0.179554640",
      "y": "0.988262337"
    },
    {
      "turn": "0",
      "x": "1.571842696",
      "y": "0.411557741"
    },
    {
      "turn": "0",
      "x": "0.930207521",
      "y": "0.831506050"
    },
    {
      "turn": "0",
      "x": "0.499603059",
      "y": "1.030243944"
    },
    {
      "turn": "0",
      "x": "1.375219768",
      "y": "0.667551627"
    },
    {
      "turn": "0",
      "x": "0.294733431",
      "y": "1.289803863"
    },
    {
      "turn": "0",
      "x": "1.703621050",
      "y": "0.706223503"
    },
    {
      "turn": "0",
      "x": "0.888074959",
      "y": "1.151534631"
    },
    {
      "turn": "0",
      "x": "1.186294121",
      "y": "1.028008210"
    },
    {
      "turn": "0",
      "x": "0.619158561",
      "y": "1.330077110"
    },
    {
      "turn": "0",
      "x": "1.502695327",
      "y": "0.964104199"
    },
    {
      "turn": "0",
      "x": "0.422656401",
      "y": "1.586163710"
    },
    {
      "turn": "0",
      "x": "1.822723908",
      "y": "1.006236761"
    },
    {
      "turn": "0",
      "x": "1.011601380",
      "y": "1.449753794"
    },
    {
      "turn": "0",
      "x": "1.309820543",
      "y": "1.326227372"
    },
    {
      "turn": "0",
      "x": "0.742684983",
      "y": "1.628296273"
    },
    {
      "turn": "0",
      "x": "1.626221749",
      "y": "1.262323361"
    },
    {
      "turn": "0",
      "x": "1.267687981",
      "y": "1.646255954"
    },
    {
      "turn": "0",
      "x": "0.998771583",
      "y": "1.824798432"
    },
    {
      "turn": "0",
      "x": "1.584089187",
      "y": "1.582351943"
    }
  ],
  "radius": "0.161395047"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 27,
  "sides": 8
}

Starter answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.449874147",
      "y": "0.402562330"
    },
    {
      "turn": "0",
      "x": "0.966545494",
      "y": "0.188550051"
    },
    {
      "turn": "0",
      "x": "0.769922565",
      "y": "0.444543937"
    },
    {
      "turn": "0",
      "x": "0.303081062",
      "y": "0.690043175"
    },
    {
      "turn": "0",
      "x": "1.273623534",
      "y": "0.288031320"
    },
    {
      "turn": "0",
      "x": "0.623129480",
      "y": "0.732024781"
    },
    {
      "turn": "0",
      "x": "1.077000606",
      "y": "0.544025206"
    },
    {
      "turn": "0",
      "x": "0.179554640",
      "y": "0.988262337"
    },
    {
      "turn": "0",
      "x": "1.571842696",
      "y": "0.411557741"
    },
    {
      "turn": "0",
      "x": "0.930207521",
      "y": "0.831506050"
    },
    {
      "turn": "0",
      "x": "0.499603059",
      "y": "1.030243944"
    },
    {
      "turn": "0",
      "x": "1.375219768",
      "y": "0.667551627"
    },
    {
      "turn": "0",
      "x": "0.294733431",
      "y": "1.289803863"
    },
    {
      "turn": "0",
      "x": "1.703621050",
      "y": "0.706223503"
    },
    {
      "turn": "0",
      "x": "0.888074959",
      "y": "1.151534631"
    },
    {
      "turn": "0",
      "x": "1.186294121",
      "y": "1.028008210"
    },
    {
      "turn": "0",
      "x": "0.619158561",
      "y": "1.330077110"
    },
    {
      "turn": "0",
      "x": "1.502695327",
      "y": "0.964104199"
    },
    {
      "turn": "0",
      "x": "0.422656401",
      "y": "1.586163710"
    },
    {
      "turn": "0",
      "x": "1.822723908",
      "y": "1.006236761"
    },
    {
      "turn": "0",
      "x": "1.011601380",
      "y": "1.449753794"
    },
    {
      "turn": "0",
      "x": "1.309820543",
      "y": "1.326227372"
    },
    {
      "turn": "0",
      "x": "0.742684983",
      "y": "1.628296273"
    },
    {
      "turn": "0",
      "x": "1.626221749",
      "y": "1.262323361"
    },
    {
      "turn": "0",
      "x": "1.267687981",
      "y": "1.646255954"
    },
    {
      "turn": "0",
      "x": "0.998771583",
      "y": "1.824798432"
    },
    {
      "turn": "0",
      "x": "1.584089187",
      "y": "1.582351943"
    }
  ],
  "radius": "0.161395047"
}

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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