P82 · Packing and covering · Classic · Hard

Equal circles in regular polygons · m = 5 · n = 33

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 = 5 · n = 33
ObjectiveMaximize circle radius

Record comparison

circle radius · Higher is better
RecordValue / intervalAuthor / holderSource
External best known[0.134134799537, 0.134134799539]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 = 5 · n = 33
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": "0.325117805",
      "y": "1.350304551"
    },
    {
      "turn": "0",
      "x": "0.325117805",
      "y": "0.994762831"
    },
    {
      "turn": "0",
      "x": "0.325117805",
      "y": "0.726493232"
    },
    {
      "turn": "0",
      "x": "0.424592679",
      "y": "0.477348038"
    },
    {
      "turn": "0",
      "x": "0.505448270",
      "y": "1.548923536"
    },
    {
      "turn": "0",
      "x": "0.526030968",
      "y": "1.172533691"
    },
    {
      "turn": "0",
      "x": "0.579528468",
      "y": "0.909652358"
    },
    {
      "turn": "0",
      "x": "0.632654964",
      "y": "0.646695796"
    },
    {
      "turn": "0",
      "x": "0.701440774",
      "y": "0.387394639"
    },
    {
      "turn": "0",
      "x": "0.709222238",
      "y": "1.368517202"
    },
    {
      "turn": "0",
      "x": "0.760587821",
      "y": "1.631823401"
    },
    {
      "turn": "0",
      "x": "0.787353302",
      "y": "1.111877153"
    },
    {
      "turn": "0",
      "x": "0.834696036",
      "y": "0.826838772"
    },
    {
      "turn": "0",
      "x": "0.900847918",
      "y": "0.566853183"
    },
    {
      "turn": "0",
      "x": "0.956688600",
      "y": "0.304459593"
    },
    {
      "turn": "0",
      "x": "0.964361788",
      "y": "1.451417067"
    },
    {
      "turn": "0",
      "x": "1.015727371",
      "y": "1.714723266"
    },
    {
      "turn": "0",
      "x": "1.034015209",
      "y": "1.006395016"
    },
    {
      "turn": "0",
      "x": "1.100167091",
      "y": "0.746409427"
    },
    {
      "turn": "0",
      "x": "1.143190333",
      "y": "1.251444746"
    },
    {
      "turn": "0",
      "x": "1.156007773",
      "y": "0.484015838"
    },
    {
      "turn": "0",
      "x": "1.215234553",
      "y": "0.222132850"
    },
    {
      "turn": "0",
      "x": "1.252245355",
      "y": "1.496547949"
    },
    {
      "turn": "0",
      "x": "1.279539180",
      "y": "1.763425495"
    },
    {
      "turn": "0",
      "x": "1.296265095",
      "y": "0.949883289"
    },
    {
      "turn": "0",
      "x": "1.362416977",
      "y": "0.689897700"
    },
    {
      "turn": "0",
      "x": "1.405440219",
      "y": "1.194933019"
    },
    {
      "turn": "0",
      "x": "1.418257659",
      "y": "0.427504110"
    },
    {
      "turn": "0",
      "x": "1.514495241",
      "y": "1.440036222"
    },
    {
      "turn": "0",
      "x": "1.563071948",
      "y": "0.977859723"
    },
    {
      "turn": "0",
      "x": "1.629223830",
      "y": "0.717874134"
    },
    {
      "turn": "0",
      "x": "1.672247072",
      "y": "1.222909453"
    },
    {
      "turn": "0",
      "x": "1.833617568",
      "y": "0.999613070"
    }
  ],
  "radius": "0.134134799"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 33,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.325117805",
      "y": "1.350304551"
    },
    {
      "turn": "0",
      "x": "0.325117805",
      "y": "0.994762831"
    },
    {
      "turn": "0",
      "x": "0.325117805",
      "y": "0.726493232"
    },
    {
      "turn": "0",
      "x": "0.424592679",
      "y": "0.477348038"
    },
    {
      "turn": "0",
      "x": "0.505448270",
      "y": "1.548923536"
    },
    {
      "turn": "0",
      "x": "0.526030968",
      "y": "1.172533691"
    },
    {
      "turn": "0",
      "x": "0.579528468",
      "y": "0.909652358"
    },
    {
      "turn": "0",
      "x": "0.632654964",
      "y": "0.646695796"
    },
    {
      "turn": "0",
      "x": "0.701440774",
      "y": "0.387394639"
    },
    {
      "turn": "0",
      "x": "0.709222238",
      "y": "1.368517202"
    },
    {
      "turn": "0",
      "x": "0.760587821",
      "y": "1.631823401"
    },
    {
      "turn": "0",
      "x": "0.787353302",
      "y": "1.111877153"
    },
    {
      "turn": "0",
      "x": "0.834696036",
      "y": "0.826838772"
    },
    {
      "turn": "0",
      "x": "0.900847918",
      "y": "0.566853183"
    },
    {
      "turn": "0",
      "x": "0.956688600",
      "y": "0.304459593"
    },
    {
      "turn": "0",
      "x": "0.964361788",
      "y": "1.451417067"
    },
    {
      "turn": "0",
      "x": "1.015727371",
      "y": "1.714723266"
    },
    {
      "turn": "0",
      "x": "1.034015209",
      "y": "1.006395016"
    },
    {
      "turn": "0",
      "x": "1.100167091",
      "y": "0.746409427"
    },
    {
      "turn": "0",
      "x": "1.143190333",
      "y": "1.251444746"
    },
    {
      "turn": "0",
      "x": "1.156007773",
      "y": "0.484015838"
    },
    {
      "turn": "0",
      "x": "1.215234553",
      "y": "0.222132850"
    },
    {
      "turn": "0",
      "x": "1.252245355",
      "y": "1.496547949"
    },
    {
      "turn": "0",
      "x": "1.279539180",
      "y": "1.763425495"
    },
    {
      "turn": "0",
      "x": "1.296265095",
      "y": "0.949883289"
    },
    {
      "turn": "0",
      "x": "1.362416977",
      "y": "0.689897700"
    },
    {
      "turn": "0",
      "x": "1.405440219",
      "y": "1.194933019"
    },
    {
      "turn": "0",
      "x": "1.418257659",
      "y": "0.427504110"
    },
    {
      "turn": "0",
      "x": "1.514495241",
      "y": "1.440036222"
    },
    {
      "turn": "0",
      "x": "1.563071948",
      "y": "0.977859723"
    },
    {
      "turn": "0",
      "x": "1.629223830",
      "y": "0.717874134"
    },
    {
      "turn": "0",
      "x": "1.672247072",
      "y": "1.222909453"
    },
    {
      "turn": "0",
      "x": "1.833617568",
      "y": "0.999613070"
    }
  ],
  "radius": "0.134134799"
}

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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