{
  "observed_masks": 13,
  "source_proof_sha256": "6b6fb4a3c75cbd81446de1d83b828e9c1c809bdb14b54db791577055481f8323",
  "manual": "https://c64online.com/wp-content/uploads/2021/03/Impossible-Mission.pdf",
  "rule": "Same color; any two pieces without overlapping opaque pixels can combine. Four pieces per solution; nonoverlap alone does not prove common puzzle membership.",
  "best_overlap_ranked": [
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      "overlap": 1,
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    {
      "overlap": 8,
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        11
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      "flips": [
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    },
    {
      "overlap": 8,
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    },
    {
      "overlap": 8,
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    },
    {
      "overlap": 8,
      "union": 296,
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        11
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      "flips": [
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        3
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    },
    {
      "overlap": 10,
      "union": 432,
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        11,
        12
      ],
      "flips": [
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        2,
        0
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    },
    {
      "overlap": 10,
      "union": 432,
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        12
      ],
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        0,
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        1
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    },
    {
      "overlap": 10,
      "union": 432,
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        10,
        11,
        12
      ],
      "flips": [
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        2
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    },
    {
      "overlap": 10,
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  "orientation_encoding": [
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  ],
  "no_password_letter_inferred": true
}