P83 · Packing and covering · Classic · Hard

Equilateral triangles in a square · n = 30

Pack n unit-side equilateral triangles into a square. Contact is allowed; interiors cannot overlap. Minimise the container square side.

Instancen = 30
ObjectiveMinimize container square side

Record comparison

container square side · Lower is better
RecordValue / intervalAuthor / holderSource
External best known[3.86619, 3.8662)30. Found by Jake LoydErich Friedman ↗
Site recordNo player record yet——

Formal definition

  • ContainerThe editor and certificate normalise the container to the unit square [0,1]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 square side = 1/(2 sin(π/3) r), where smaller is better. Pages, leaderboards, and literature records share this unit with automatic conversion.
Open full editor ↗

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 Equilateral triangles in a square n = 30
LAYOUT & HISTORY

Starter layout

Inspect the layout, solver notes and record history.

Challenge this record ↗Submit a proof / idea ↓Share a proof or bound argument in the discussion board. Accepted contributions earn proof points.
ANSWER FORMAT

How to write your answer

the unit square [0,1]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": "0.267949192",
      "x": "0.189110637",
      "y": "0.925333476"
    },
    {
      "turn": "0.267949192",
      "x": "0.447763063",
      "y": "0.925333476"
    },
    {
      "turn": "0.267949192",
      "x": "0.706415490",
      "y": "0.925333476"
    },
    {
      "turn": "0.538836745",
      "x": "0.917870852",
      "y": "0.875279664"
    },
    {
      "turn": "-0.267949192",
      "x": "0.318436850",
      "y": "0.850666952"
    },
    {
      "turn": "-0.267949192",
      "x": "0.577089277",
      "y": "0.850666952"
    },
    {
      "turn": "-0.029375026",
      "x": "0.835741704",
      "y": "0.750559327"
    },
    {
      "turn": "0.000000000",
      "x": "0.074666524",
      "y": "0.755857291"
    },
    {
      "turn": "0.267949192",
      "x": "0.374463527",
      "y": "0.701333903"
    },
    {
      "turn": "0.267949192",
      "x": "0.633115953",
      "y": "0.701333903"
    },
    {
      "turn": "-0.267949192",
      "x": "0.503789740",
      "y": "0.626667379"
    },
    {
      "turn": "-0.577350269",
      "x": "0.160034596",
      "y": "0.632709619"
    },
    {
      "turn": "0.538836745",
      "x": "0.917870852",
      "y": "0.624687731"
    },
    {
      "turn": "0.000000000",
      "x": "0.085368072",
      "y": "0.503383406"
    },
    {
      "turn": "0.000000000",
      "x": "0.309367645",
      "y": "0.503366504"
    },
    {
      "turn": "-0.021100813",
      "x": "0.835617129",
      "y": "0.497500927"
    },
    {
      "turn": "0.549554476",
      "x": "0.686063161",
      "y": "0.495419428"
    },
    {
      "turn": "0.577350269",
      "x": "0.160034596",
      "y": "0.374057193"
    },
    {
      "turn": "-0.577350269",
      "x": "0.925333476",
      "y": "0.370641181"
    },
    {
      "turn": "0.267949192",
      "x": "0.492127826",
      "y": "0.373332621"
    },
    {
      "turn": "-0.267949192",
      "x": "0.362801613",
      "y": "0.298666097"
    },
    {
      "turn": "-0.267949192",
      "x": "0.621454040",
      "y": "0.298666097"
    },
    {
      "turn": "0.000000000",
      "x": "0.074666524",
      "y": "0.250909521"
    },
    {
      "turn": "0.053294896",
      "x": "0.824021241",
      "y": "0.241314968"
    },
    {
      "turn": "-0.508411637",
      "x": "0.912010621",
      "y": "0.120657484"
    },
    {
      "turn": "0.267949192",
      "x": "0.306716388",
      "y": "0.149333048"
    },
    {
      "turn": "0.267949192",
      "x": "0.565368815",
      "y": "0.149333048"
    },
    {
      "turn": "-0.267949192",
      "x": "0.177390174",
      "y": "0.074666524"
    },
    {
      "turn": "-0.267949192",
      "x": "0.436042601",
      "y": "0.074666524"
    },
    {
      "turn": "-0.267949192",
      "x": "0.694695028",
      "y": "0.074666524"
    }
  ],
  "radius": "0.149333047"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 30,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0.267949192",
      "x": "0.189110637",
      "y": "0.925333476"
    },
    {
      "turn": "0.267949192",
      "x": "0.447763063",
      "y": "0.925333476"
    },
    {
      "turn": "0.267949192",
      "x": "0.706415490",
      "y": "0.925333476"
    },
    {
      "turn": "0.538836745",
      "x": "0.917870852",
      "y": "0.875279664"
    },
    {
      "turn": "-0.267949192",
      "x": "0.318436850",
      "y": "0.850666952"
    },
    {
      "turn": "-0.267949192",
      "x": "0.577089277",
      "y": "0.850666952"
    },
    {
      "turn": "-0.029375026",
      "x": "0.835741704",
      "y": "0.750559327"
    },
    {
      "turn": "0.000000000",
      "x": "0.074666524",
      "y": "0.755857291"
    },
    {
      "turn": "0.267949192",
      "x": "0.374463527",
      "y": "0.701333903"
    },
    {
      "turn": "0.267949192",
      "x": "0.633115953",
      "y": "0.701333903"
    },
    {
      "turn": "-0.267949192",
      "x": "0.503789740",
      "y": "0.626667379"
    },
    {
      "turn": "-0.577350269",
      "x": "0.160034596",
      "y": "0.632709619"
    },
    {
      "turn": "0.538836745",
      "x": "0.917870852",
      "y": "0.624687731"
    },
    {
      "turn": "0.000000000",
      "x": "0.085368072",
      "y": "0.503383406"
    },
    {
      "turn": "0.000000000",
      "x": "0.309367645",
      "y": "0.503366504"
    },
    {
      "turn": "-0.021100813",
      "x": "0.835617129",
      "y": "0.497500927"
    },
    {
      "turn": "0.549554476",
      "x": "0.686063161",
      "y": "0.495419428"
    },
    {
      "turn": "0.577350269",
      "x": "0.160034596",
      "y": "0.374057193"
    },
    {
      "turn": "-0.577350269",
      "x": "0.925333476",
      "y": "0.370641181"
    },
    {
      "turn": "0.267949192",
      "x": "0.492127826",
      "y": "0.373332621"
    },
    {
      "turn": "-0.267949192",
      "x": "0.362801613",
      "y": "0.298666097"
    },
    {
      "turn": "-0.267949192",
      "x": "0.621454040",
      "y": "0.298666097"
    },
    {
      "turn": "0.000000000",
      "x": "0.074666524",
      "y": "0.250909521"
    },
    {
      "turn": "0.053294896",
      "x": "0.824021241",
      "y": "0.241314968"
    },
    {
      "turn": "-0.508411637",
      "x": "0.912010621",
      "y": "0.120657484"
    },
    {
      "turn": "0.267949192",
      "x": "0.306716388",
      "y": "0.149333048"
    },
    {
      "turn": "0.267949192",
      "x": "0.565368815",
      "y": "0.149333048"
    },
    {
      "turn": "-0.267949192",
      "x": "0.177390174",
      "y": "0.074666524"
    },
    {
      "turn": "-0.267949192",
      "x": "0.436042601",
      "y": "0.074666524"
    },
    {
      "turn": "-0.267949192",
      "x": "0.694695028",
      "y": "0.074666524"
    }
  ],
  "radius": "0.149333047"
}

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

Discuss strategies, share construction methods, or ask questions. Any signed-in user can post under their public byline and unique #UID. New posts appear after moderation.