P85 · Packing and covering · Classic · Hard

Squares in an equilateral triangle · n = 17

Pack n unit squares into an equilateral triangle container with boundary contact allowed and disjoint interiors, minimising the side length of the container triangle.

Instancen = 17
ObjectiveMinimize container triangle side

Record comparison

container triangle side · Lower is better
RecordValue / intervalAuthor / holderSource
External best known[7.301, 7.302)David W. CantrellErich Friedman ↗
Site recordNo player record yet——

Formal definition

  • ContainerThe editor and certificate normalise the container to the equilateral triangle with vertices (0,0), (1,0), and (1/2,√3/2), 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 triangle side = 1/(2 sin(π/4) 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 Squares in an equilateral triangle n = 17
LAYOUT & HISTORY

Starter layout

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ANSWER FORMAT

How to write your answer

the equilateral triangle with vertices (0,0), (1,0), (1/2,√3/2)

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": "0.131652498",
      "x": "0.485528115",
      "y": "0.703995978"
    },
    {
      "turn": "0.131652498",
      "x": "0.417046422",
      "y": "0.585382206"
    },
    {
      "turn": "0.131652498",
      "x": "0.564603964",
      "y": "0.567032591"
    },
    {
      "turn": "0.131652498",
      "x": "0.348564729",
      "y": "0.466768433"
    },
    {
      "turn": "0.131652498",
      "x": "0.497116220",
      "y": "0.447844962"
    },
    {
      "turn": "0.131652498",
      "x": "0.280083035",
      "y": "0.348154661"
    },
    {
      "turn": "0.414213562",
      "x": "0.645985401",
      "y": "0.342944326"
    },
    {
      "turn": "0.131652498",
      "x": "0.427640577",
      "y": "0.329805047"
    },
    {
      "turn": "0.131652498",
      "x": "0.211601342",
      "y": "0.229540889"
    },
    {
      "turn": "0.414213562",
      "x": "0.578515685",
      "y": "0.205518674"
    },
    {
      "turn": "0.414213562",
      "x": "0.715479072",
      "y": "0.205518674"
    },
    {
      "turn": "0.414213562",
      "x": "0.441552299",
      "y": "0.167775621"
    },
    {
      "turn": "-0.231047659",
      "x": "0.304868993",
      "y": "0.087031700"
    },
    {
      "turn": "0.414223413",
      "x": "0.149356608",
      "y": "0.069343064"
    },
    {
      "turn": "0.414213562",
      "x": "0.578515685",
      "y": "0.068548295"
    },
    {
      "turn": "0.414213562",
      "x": "0.715479072",
      "y": "0.068548295"
    },
    {
      "turn": "0.414213562",
      "x": "0.852442459",
      "y": "0.068481693"
    }
  ],
  "radius": "0.096847738"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 17,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0.131652498",
      "x": "0.485528115",
      "y": "0.703995978"
    },
    {
      "turn": "0.131652498",
      "x": "0.417046422",
      "y": "0.585382206"
    },
    {
      "turn": "0.131652498",
      "x": "0.564603964",
      "y": "0.567032591"
    },
    {
      "turn": "0.131652498",
      "x": "0.348564729",
      "y": "0.466768433"
    },
    {
      "turn": "0.131652498",
      "x": "0.497116220",
      "y": "0.447844962"
    },
    {
      "turn": "0.131652498",
      "x": "0.280083035",
      "y": "0.348154661"
    },
    {
      "turn": "0.414213562",
      "x": "0.645985401",
      "y": "0.342944326"
    },
    {
      "turn": "0.131652498",
      "x": "0.427640577",
      "y": "0.329805047"
    },
    {
      "turn": "0.131652498",
      "x": "0.211601342",
      "y": "0.229540889"
    },
    {
      "turn": "0.414213562",
      "x": "0.578515685",
      "y": "0.205518674"
    },
    {
      "turn": "0.414213562",
      "x": "0.715479072",
      "y": "0.205518674"
    },
    {
      "turn": "0.414213562",
      "x": "0.441552299",
      "y": "0.167775621"
    },
    {
      "turn": "-0.231047659",
      "x": "0.304868993",
      "y": "0.087031700"
    },
    {
      "turn": "0.414223413",
      "x": "0.149356608",
      "y": "0.069343064"
    },
    {
      "turn": "0.414213562",
      "x": "0.578515685",
      "y": "0.068548295"
    },
    {
      "turn": "0.414213562",
      "x": "0.715479072",
      "y": "0.068548295"
    },
    {
      "turn": "0.414213562",
      "x": "0.852442459",
      "y": "0.068481693"
    }
  ],
  "radius": "0.096847738"
}

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

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