P82 · Packing and covering · Classic · Hard

Equal circles in regular polygons · m = 6 · n = 39

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 = 6 · n = 39
ObjectiveMaximize circle radius

Record comparison

circle radius · Higher is better
RecordValue / intervalAuthor / holderSource
External best known[0.129882647186, 0.129882647188]Eckard SpechtPackomania ↗
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 = 6 · n = 39
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": "0.792063818",
      "y": "0.263857243"
    },
    {
      "turn": "0",
      "x": "1.051829112",
      "y": "0.263857243"
    },
    {
      "turn": "0",
      "x": "1.311594406",
      "y": "0.263857243"
    },
    {
      "turn": "0",
      "x": "0.539623504",
      "y": "0.325109968"
    },
    {
      "turn": "0",
      "x": "1.516897431",
      "y": "0.423007099"
    },
    {
      "turn": "0",
      "x": "0.921946465",
      "y": "0.488820587"
    },
    {
      "turn": "0",
      "x": "1.181711759",
      "y": "0.488820587"
    },
    {
      "turn": "0",
      "x": "0.409740857",
      "y": "0.550073312"
    },
    {
      "turn": "0",
      "x": "0.669506151",
      "y": "0.550073312"
    },
    {
      "turn": "0",
      "x": "1.387014783",
      "y": "0.647970443"
    },
    {
      "turn": "0",
      "x": "1.646780078",
      "y": "0.647970443"
    },
    {
      "turn": "0",
      "x": "0.888412139",
      "y": "0.746412235"
    },
    {
      "turn": "0",
      "x": "1.148151805",
      "y": "0.750061020"
    },
    {
      "turn": "0",
      "x": "0.279858210",
      "y": "0.775036656"
    },
    {
      "turn": "0",
      "x": "0.539623504",
      "y": "0.775036656"
    },
    {
      "turn": "0",
      "x": "1.516897431",
      "y": "0.872933787"
    },
    {
      "turn": "0",
      "x": "1.776662725",
      "y": "0.872933787"
    },
    {
      "turn": "0",
      "x": "0.729721203",
      "y": "0.952070192"
    },
    {
      "turn": "0",
      "x": "1.031190112",
      "y": "0.982004915"
    },
    {
      "turn": "0",
      "x": "0.149975563",
      "y": "1.000000000"
    },
    {
      "turn": "0",
      "x": "0.409740857",
      "y": "1.000000000"
    },
    {
      "turn": "0",
      "x": "1.290331357",
      "y": "1.000000000"
    },
    {
      "turn": "0",
      "x": "1.513656963",
      "y": "1.132678868"
    },
    {
      "turn": "0",
      "x": "1.773422257",
      "y": "1.132678868"
    },
    {
      "turn": "0",
      "x": "0.599838556",
      "y": "1.177033536"
    },
    {
      "turn": "0",
      "x": "0.859603851",
      "y": "1.177033536"
    },
    {
      "turn": "0",
      "x": "0.279858210",
      "y": "1.224963344"
    },
    {
      "turn": "0",
      "x": "1.151366571",
      "y": "1.226779439"
    },
    {
      "turn": "0",
      "x": "1.383774315",
      "y": "1.357642212"
    },
    {
      "turn": "0",
      "x": "1.643539610",
      "y": "1.357642212"
    },
    {
      "turn": "0",
      "x": "0.668540494",
      "y": "1.427549108"
    },
    {
      "turn": "0",
      "x": "0.928305788",
      "y": "1.427549108"
    },
    {
      "turn": "0",
      "x": "0.409740857",
      "y": "1.449926688"
    },
    {
      "turn": "0",
      "x": "1.174240699",
      "y": "1.511179413"
    },
    {
      "turn": "0",
      "x": "1.513656963",
      "y": "1.582605556"
    },
    {
      "turn": "0",
      "x": "0.798423141",
      "y": "1.652512452"
    },
    {
      "turn": "0",
      "x": "0.539623504",
      "y": "1.674890032"
    },
    {
      "turn": "0",
      "x": "1.044358052",
      "y": "1.736142757"
    },
    {
      "turn": "0",
      "x": "1.304123346",
      "y": "1.736142757"
    }
  ],
  "radius": "0.129882646"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 39,
  "sides": 6
}

Starter answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.792063818",
      "y": "0.263857243"
    },
    {
      "turn": "0",
      "x": "1.051829112",
      "y": "0.263857243"
    },
    {
      "turn": "0",
      "x": "1.311594406",
      "y": "0.263857243"
    },
    {
      "turn": "0",
      "x": "0.539623504",
      "y": "0.325109968"
    },
    {
      "turn": "0",
      "x": "1.516897431",
      "y": "0.423007099"
    },
    {
      "turn": "0",
      "x": "0.921946465",
      "y": "0.488820587"
    },
    {
      "turn": "0",
      "x": "1.181711759",
      "y": "0.488820587"
    },
    {
      "turn": "0",
      "x": "0.409740857",
      "y": "0.550073312"
    },
    {
      "turn": "0",
      "x": "0.669506151",
      "y": "0.550073312"
    },
    {
      "turn": "0",
      "x": "1.387014783",
      "y": "0.647970443"
    },
    {
      "turn": "0",
      "x": "1.646780078",
      "y": "0.647970443"
    },
    {
      "turn": "0",
      "x": "0.888412139",
      "y": "0.746412235"
    },
    {
      "turn": "0",
      "x": "1.148151805",
      "y": "0.750061020"
    },
    {
      "turn": "0",
      "x": "0.279858210",
      "y": "0.775036656"
    },
    {
      "turn": "0",
      "x": "0.539623504",
      "y": "0.775036656"
    },
    {
      "turn": "0",
      "x": "1.516897431",
      "y": "0.872933787"
    },
    {
      "turn": "0",
      "x": "1.776662725",
      "y": "0.872933787"
    },
    {
      "turn": "0",
      "x": "0.729721203",
      "y": "0.952070192"
    },
    {
      "turn": "0",
      "x": "1.031190112",
      "y": "0.982004915"
    },
    {
      "turn": "0",
      "x": "0.149975563",
      "y": "1.000000000"
    },
    {
      "turn": "0",
      "x": "0.409740857",
      "y": "1.000000000"
    },
    {
      "turn": "0",
      "x": "1.290331357",
      "y": "1.000000000"
    },
    {
      "turn": "0",
      "x": "1.513656963",
      "y": "1.132678868"
    },
    {
      "turn": "0",
      "x": "1.773422257",
      "y": "1.132678868"
    },
    {
      "turn": "0",
      "x": "0.599838556",
      "y": "1.177033536"
    },
    {
      "turn": "0",
      "x": "0.859603851",
      "y": "1.177033536"
    },
    {
      "turn": "0",
      "x": "0.279858210",
      "y": "1.224963344"
    },
    {
      "turn": "0",
      "x": "1.151366571",
      "y": "1.226779439"
    },
    {
      "turn": "0",
      "x": "1.383774315",
      "y": "1.357642212"
    },
    {
      "turn": "0",
      "x": "1.643539610",
      "y": "1.357642212"
    },
    {
      "turn": "0",
      "x": "0.668540494",
      "y": "1.427549108"
    },
    {
      "turn": "0",
      "x": "0.928305788",
      "y": "1.427549108"
    },
    {
      "turn": "0",
      "x": "0.409740857",
      "y": "1.449926688"
    },
    {
      "turn": "0",
      "x": "1.174240699",
      "y": "1.511179413"
    },
    {
      "turn": "0",
      "x": "1.513656963",
      "y": "1.582605556"
    },
    {
      "turn": "0",
      "x": "0.798423141",
      "y": "1.652512452"
    },
    {
      "turn": "0",
      "x": "0.539623504",
      "y": "1.674890032"
    },
    {
      "turn": "0",
      "x": "1.044358052",
      "y": "1.736142757"
    },
    {
      "turn": "0",
      "x": "1.304123346",
      "y": "1.736142757"
    }
  ],
  "radius": "0.129882646"
}

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

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