P85 · Packing and covering · Classic · Hard

Squares in an equilateral triangle · n = 23

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 = 23
ObjectiveMinimize container triangle side

Record comparison

container triangle side · Lower is better
RecordValue / intervalAuthor / holderSource
External best known[8.301, 8.302)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 = 23
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": "0.487271459",
      "y": "0.723514723"
    },
    {
      "turn": "0.131652498",
      "x": "0.427039359",
      "y": "0.619189664"
    },
    {
      "turn": "0.131652498",
      "x": "0.556821499",
      "y": "0.603050522"
    },
    {
      "turn": "0.131652498",
      "x": "0.367494001",
      "y": "0.514468114"
    },
    {
      "turn": "0.131652498",
      "x": "0.498355296",
      "y": "0.497705921"
    },
    {
      "turn": "0.414210431",
      "x": "0.627737227",
      "y": "0.422158883"
    },
    {
      "turn": "0.131652498",
      "x": "0.306575157",
      "y": "0.410539547"
    },
    {
      "turn": "0.131652498",
      "x": "0.437138539",
      "y": "0.393949354"
    },
    {
      "turn": "0.131652498",
      "x": "0.246343056",
      "y": "0.306214488"
    },
    {
      "turn": "0.414208565",
      "x": "0.569329776",
      "y": "0.301679017"
    },
    {
      "turn": "0.414209957",
      "x": "0.689794313",
      "y": "0.301678380"
    },
    {
      "turn": "0.131652498",
      "x": "0.376125196",
      "y": "0.290075345"
    },
    {
      "turn": "0.131652498",
      "x": "0.186110955",
      "y": "0.201889429"
    },
    {
      "turn": "0.414213562",
      "x": "0.508825255",
      "y": "0.181198622"
    },
    {
      "turn": "0.414207456",
      "x": "0.629290085",
      "y": "0.181197051"
    },
    {
      "turn": "0.414200653",
      "x": "0.749754986",
      "y": "0.181196175"
    },
    {
      "turn": "0.414213562",
      "x": "0.388361054",
      "y": "0.147564664"
    },
    {
      "turn": "-0.231047658",
      "x": "0.268143194",
      "y": "0.076547495"
    },
    {
      "turn": "0.414224323",
      "x": "0.130700788",
      "y": "0.060871247"
    },
    {
      "turn": "0.414213562",
      "x": "0.508825255",
      "y": "0.060715696"
    },
    {
      "turn": "0.414213562",
      "x": "0.629289457",
      "y": "0.060714821"
    },
    {
      "turn": "0.414213562",
      "x": "0.749753658",
      "y": "0.060714821"
    },
    {
      "turn": "0.414213562",
      "x": "0.870217860",
      "y": "0.060232101"
    }
  ],
  "radius": "0.085181053"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 23,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0.131652498",
      "x": "0.487271459",
      "y": "0.723514723"
    },
    {
      "turn": "0.131652498",
      "x": "0.427039359",
      "y": "0.619189664"
    },
    {
      "turn": "0.131652498",
      "x": "0.556821499",
      "y": "0.603050522"
    },
    {
      "turn": "0.131652498",
      "x": "0.367494001",
      "y": "0.514468114"
    },
    {
      "turn": "0.131652498",
      "x": "0.498355296",
      "y": "0.497705921"
    },
    {
      "turn": "0.414210431",
      "x": "0.627737227",
      "y": "0.422158883"
    },
    {
      "turn": "0.131652498",
      "x": "0.306575157",
      "y": "0.410539547"
    },
    {
      "turn": "0.131652498",
      "x": "0.437138539",
      "y": "0.393949354"
    },
    {
      "turn": "0.131652498",
      "x": "0.246343056",
      "y": "0.306214488"
    },
    {
      "turn": "0.414208565",
      "x": "0.569329776",
      "y": "0.301679017"
    },
    {
      "turn": "0.414209957",
      "x": "0.689794313",
      "y": "0.301678380"
    },
    {
      "turn": "0.131652498",
      "x": "0.376125196",
      "y": "0.290075345"
    },
    {
      "turn": "0.131652498",
      "x": "0.186110955",
      "y": "0.201889429"
    },
    {
      "turn": "0.414213562",
      "x": "0.508825255",
      "y": "0.181198622"
    },
    {
      "turn": "0.414207456",
      "x": "0.629290085",
      "y": "0.181197051"
    },
    {
      "turn": "0.414200653",
      "x": "0.749754986",
      "y": "0.181196175"
    },
    {
      "turn": "0.414213562",
      "x": "0.388361054",
      "y": "0.147564664"
    },
    {
      "turn": "-0.231047658",
      "x": "0.268143194",
      "y": "0.076547495"
    },
    {
      "turn": "0.414224323",
      "x": "0.130700788",
      "y": "0.060871247"
    },
    {
      "turn": "0.414213562",
      "x": "0.508825255",
      "y": "0.060715696"
    },
    {
      "turn": "0.414213562",
      "x": "0.629289457",
      "y": "0.060714821"
    },
    {
      "turn": "0.414213562",
      "x": "0.749753658",
      "y": "0.060714821"
    },
    {
      "turn": "0.414213562",
      "x": "0.870217860",
      "y": "0.060232101"
    }
  ],
  "radius": "0.085181053"
}

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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