P85 · Packing and covering · Classic · Hard

Squares in an equilateral triangle · n = 40

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 = 40
ObjectiveMinimize container triangle side

Record comparison

container triangle side · Lower is better
RecordValue / intervalAuthor / holderSource
External best known[10.4641, 10.46411)Bhavithran AnanthanErich 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 = 40
LAYOUT & HISTORY

Starter layout

Inspect the layout, solver notes and record history.

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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": "0.139014541",
      "x": "0.490110712",
      "y": "0.749757764"
    },
    {
      "turn": "-0.123429023",
      "x": "0.561519369",
      "y": "0.660620124"
    },
    {
      "turn": "0.131652498",
      "x": "0.432368715",
      "y": "0.653319760"
    },
    {
      "turn": "-0.131652498",
      "x": "0.611127628",
      "y": "0.577981885"
    },
    {
      "turn": "0.131652498",
      "x": "0.381454130",
      "y": "0.565133113"
    },
    {
      "turn": "0.131652498",
      "x": "0.489902389",
      "y": "0.561841364"
    },
    {
      "turn": "-0.134829526",
      "x": "0.652094646",
      "y": "0.490844535"
    },
    {
      "turn": "0.123879053",
      "x": "0.334120273",
      "y": "0.481238862"
    },
    {
      "turn": "0.131652498",
      "x": "0.443875654",
      "y": "0.478066161"
    },
    {
      "turn": "0.152448479",
      "x": "0.527449966",
      "y": "0.427875972"
    },
    {
      "turn": "-0.133299825",
      "x": "0.706836569",
      "y": "0.411900215"
    },
    {
      "turn": "0.127536167",
      "x": "0.285711072",
      "y": "0.398444519"
    },
    {
      "turn": "0.131652498",
      "x": "0.396333211",
      "y": "0.395166053"
    },
    {
      "turn": "0.197249610",
      "x": "0.604267467",
      "y": "0.360036818"
    },
    {
      "turn": "0.156096206",
      "x": "0.479998137",
      "y": "0.344345038"
    },
    {
      "turn": "-0.130619735",
      "x": "0.748321517",
      "y": "0.325239844"
    },
    {
      "turn": "0.132014560",
      "x": "0.238075541",
      "y": "0.315114613"
    },
    {
      "turn": "0.131652498",
      "x": "0.347534848",
      "y": "0.312991050"
    },
    {
      "turn": "0.245026390",
      "x": "0.552631750",
      "y": "0.260343476"
    },
    {
      "turn": "0.282386149",
      "x": "0.434417420",
      "y": "0.249024471"
    },
    {
      "turn": "-0.134136147",
      "x": "0.801121920",
      "y": "0.244986703"
    },
    {
      "turn": "0.298251692",
      "x": "0.651528258",
      "y": "0.244202218"
    },
    {
      "turn": "0.131652498",
      "x": "0.189548887",
      "y": "0.232743482"
    },
    {
      "turn": "0.131652498",
      "x": "0.312202526",
      "y": "0.223041426"
    },
    {
      "turn": "-0.105171451",
      "x": "0.737367815",
      "y": "0.162395751"
    },
    {
      "turn": "-0.127593111",
      "x": "0.850573838",
      "y": "0.162488850"
    },
    {
      "turn": "0.371675391",
      "x": "0.611963484",
      "y": "0.147812075"
    },
    {
      "turn": "0.131652498",
      "x": "0.141293211",
      "y": "0.149162199"
    },
    {
      "turn": "0.363879433",
      "x": "0.515428020",
      "y": "0.149004586"
    },
    {
      "turn": "0.131652498",
      "x": "0.250990335",
      "y": "0.148033550"
    },
    {
      "turn": "0.347033730",
      "x": "0.416851128",
      "y": "0.149481748"
    },
    {
      "turn": "0.131652498",
      "x": "0.093323166",
      "y": "0.066075643"
    },
    {
      "turn": "0.131652498",
      "x": "0.203207925",
      "y": "0.065271987"
    },
    {
      "turn": "0.414213562",
      "x": "0.419219108",
      "y": "0.047870714"
    },
    {
      "turn": "0.414213562",
      "x": "0.705913572",
      "y": "0.048517341"
    },
    {
      "turn": "0.414213562",
      "x": "0.801478393",
      "y": "0.048996581"
    },
    {
      "turn": "0.414213562",
      "x": "0.897043214",
      "y": "0.047782411"
    },
    {
      "turn": "0.414213562",
      "x": "0.323654287",
      "y": "0.047782411"
    },
    {
      "turn": "0.414213562",
      "x": "0.514783929",
      "y": "0.047784526"
    },
    {
      "turn": "0.414213562",
      "x": "0.610348751",
      "y": "0.047784542"
    }
  ],
  "radius": "0.067574532"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 40,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0.139014541",
      "x": "0.490110712",
      "y": "0.749757764"
    },
    {
      "turn": "-0.123429023",
      "x": "0.561519369",
      "y": "0.660620124"
    },
    {
      "turn": "0.131652498",
      "x": "0.432368715",
      "y": "0.653319760"
    },
    {
      "turn": "-0.131652498",
      "x": "0.611127628",
      "y": "0.577981885"
    },
    {
      "turn": "0.131652498",
      "x": "0.381454130",
      "y": "0.565133113"
    },
    {
      "turn": "0.131652498",
      "x": "0.489902389",
      "y": "0.561841364"
    },
    {
      "turn": "-0.134829526",
      "x": "0.652094646",
      "y": "0.490844535"
    },
    {
      "turn": "0.123879053",
      "x": "0.334120273",
      "y": "0.481238862"
    },
    {
      "turn": "0.131652498",
      "x": "0.443875654",
      "y": "0.478066161"
    },
    {
      "turn": "0.152448479",
      "x": "0.527449966",
      "y": "0.427875972"
    },
    {
      "turn": "-0.133299825",
      "x": "0.706836569",
      "y": "0.411900215"
    },
    {
      "turn": "0.127536167",
      "x": "0.285711072",
      "y": "0.398444519"
    },
    {
      "turn": "0.131652498",
      "x": "0.396333211",
      "y": "0.395166053"
    },
    {
      "turn": "0.197249610",
      "x": "0.604267467",
      "y": "0.360036818"
    },
    {
      "turn": "0.156096206",
      "x": "0.479998137",
      "y": "0.344345038"
    },
    {
      "turn": "-0.130619735",
      "x": "0.748321517",
      "y": "0.325239844"
    },
    {
      "turn": "0.132014560",
      "x": "0.238075541",
      "y": "0.315114613"
    },
    {
      "turn": "0.131652498",
      "x": "0.347534848",
      "y": "0.312991050"
    },
    {
      "turn": "0.245026390",
      "x": "0.552631750",
      "y": "0.260343476"
    },
    {
      "turn": "0.282386149",
      "x": "0.434417420",
      "y": "0.249024471"
    },
    {
      "turn": "-0.134136147",
      "x": "0.801121920",
      "y": "0.244986703"
    },
    {
      "turn": "0.298251692",
      "x": "0.651528258",
      "y": "0.244202218"
    },
    {
      "turn": "0.131652498",
      "x": "0.189548887",
      "y": "0.232743482"
    },
    {
      "turn": "0.131652498",
      "x": "0.312202526",
      "y": "0.223041426"
    },
    {
      "turn": "-0.105171451",
      "x": "0.737367815",
      "y": "0.162395751"
    },
    {
      "turn": "-0.127593111",
      "x": "0.850573838",
      "y": "0.162488850"
    },
    {
      "turn": "0.371675391",
      "x": "0.611963484",
      "y": "0.147812075"
    },
    {
      "turn": "0.131652498",
      "x": "0.141293211",
      "y": "0.149162199"
    },
    {
      "turn": "0.363879433",
      "x": "0.515428020",
      "y": "0.149004586"
    },
    {
      "turn": "0.131652498",
      "x": "0.250990335",
      "y": "0.148033550"
    },
    {
      "turn": "0.347033730",
      "x": "0.416851128",
      "y": "0.149481748"
    },
    {
      "turn": "0.131652498",
      "x": "0.093323166",
      "y": "0.066075643"
    },
    {
      "turn": "0.131652498",
      "x": "0.203207925",
      "y": "0.065271987"
    },
    {
      "turn": "0.414213562",
      "x": "0.419219108",
      "y": "0.047870714"
    },
    {
      "turn": "0.414213562",
      "x": "0.705913572",
      "y": "0.048517341"
    },
    {
      "turn": "0.414213562",
      "x": "0.801478393",
      "y": "0.048996581"
    },
    {
      "turn": "0.414213562",
      "x": "0.897043214",
      "y": "0.047782411"
    },
    {
      "turn": "0.414213562",
      "x": "0.323654287",
      "y": "0.047782411"
    },
    {
      "turn": "0.414213562",
      "x": "0.514783929",
      "y": "0.047784526"
    },
    {
      "turn": "0.414213562",
      "x": "0.610348751",
      "y": "0.047784542"
    }
  ],
  "radius": "0.067574532"
}

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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