{
  "bands": [
    {
      "description": "Load, halt, and copy fixed amounts of input. Canonical programs and early tool baselines establish the floor.",
      "id": "foundations",
      "number": "1",
      "title": "Foundations"
    },
    {
      "description": "Route inputs, realize small maps, and fit public lookup tables. Placement across these tasks is an editorial estimate.",
      "id": "construction",
      "number": "2",
      "title": "Input-dependent construction"
    },
    {
      "description": "Increase byte coverage, then reach all 256 first-byte values. Several milestones share a winning program.",
      "id": "coverage",
      "number": "3",
      "title": "Coverage to full XOR"
    },
    {
      "description": "Compress full XOR and solve a neighboring 256-byte rotation task. The XOR size ordering follows from nested limits.",
      "id": "compact",
      "number": "4",
      "title": "Compact arithmetic"
    },
    {
      "description": "Transform several bytes within tight limits. Cross-task placement is provisional; first-byte sweeps do not enumerate all byte tuples.",
      "id": "multibyte",
      "number": "5",
      "title": "Multiple-byte transforms"
    },
    {
      "description": "Handle streams with an unknown endpoint: copy, count, accumulate, then reverse. These frontier placements await successful constructions.",
      "id": "streams",
      "number": "6",
      "title": "Variable-length programs"
    }
  ],
  "generated": "2026-09-07 13:24 UTC · dc828bb0b437",
  "ordering": "Editorial curriculum, easiest to frontier; not a measured model ranking or equal-interval scale. Status changes do not reorder tasks.",
  "revision": "2026-09-05",
  "rungs": [
    {
      "placement": {
        "band": "foundations",
        "calibration": "baseline",
        "rationale": "Verified canonical or tool baseline. Similar slots are retained for historical continuity.",
        "rung_id": "L0.R0.hello-world",
        "summary": "Load a valid program and stop cleanly.",
        "title": "Halt without output"
      },
      "rank": 1,
      "rung_digest": "ce214c5925137c1d",
      "verification": {
        "detail": "Fixed public examples, with exact output and halt required. Canonical copying solutions may be more general than the tested suite; the suite alone does not establish that.",
        "label": "Public example suite",
        "score_unit": "cases in worst epoch"
      }
    },
    {
      "placement": {
        "band": "foundations",
        "calibration": "baseline",
        "rationale": "Verified canonical or tool baseline. Similar slots are retained for historical continuity.",
        "rung_id": "L0.R1.echo-1-demo",
        "summary": "Copy one input byte; canonical baseline.",
        "title": "Echo one byte · demo"
      },
      "rank": 2,
      "rung_digest": "4632b8a611b4bdbe",
      "verification": {
        "detail": "Fixed public examples, with exact output and halt required. Canonical copying solutions may be more general than the tested suite; the suite alone does not establish that.",
        "label": "Public example suite",
        "score_unit": "cases in worst epoch"
      }
    },
    {
      "placement": {
        "band": "foundations",
        "calibration": "baseline",
        "rationale": "Verified canonical or tool baseline. Similar slots are retained for historical continuity.",
        "rung_id": "L1.R0.echo-1",
        "summary": "Copy one input byte and halt.",
        "title": "Echo one byte"
      },
      "rank": 3,
      "rung_digest": "3db2543f3e4a246d",
      "verification": {
        "detail": "Fixed public examples, with exact output and halt required. Canonical copying solutions may be more general than the tested suite; the suite alone does not establish that.",
        "label": "Public example suite",
        "score_unit": "cases in worst epoch"
      }
    },
    {
      "placement": {
        "band": "foundations",
        "calibration": "baseline",
        "rationale": "Verified canonical or tool baseline. Similar slots are retained for historical continuity.",
        "rung_id": "L2.R1.reverse-1",
        "summary": "A one-byte reversal leaves the byte unchanged.",
        "title": "Reverse one byte · identity"
      },
      "rank": 4,
      "rung_digest": "505c5aa696afbd91",
      "verification": {
        "detail": "Every first-byte value is tested for each of 1 cases over 256 epochs. The remaining input bytes are public deterministic samples. This does not exhaust all input strings or prove suffix independence.",
        "label": "256-value first-byte sweep",
        "score_unit": "cases across the sweep"
      }
    },
    {
      "placement": {
        "band": "foundations",
        "calibration": "baseline",
        "rationale": "Verified canonical or tool baseline. Similar slots are retained for historical continuity.",
        "rung_id": "L1.R1.echo-2",
        "summary": "Copy two bytes in order.",
        "title": "Echo two bytes"
      },
      "rank": 5,
      "rung_digest": "51730d0b5fe56c7d",
      "verification": {
        "detail": "Fixed public examples, with exact output and halt required. Canonical copying solutions may be more general than the tested suite; the suite alone does not establish that.",
        "label": "Public example suite",
        "score_unit": "cases in worst epoch"
      }
    },
    {
      "placement": {
        "band": "foundations",
        "calibration": "baseline",
        "rationale": "Verified canonical or tool baseline. Similar slots are retained for historical continuity.",
        "rung_id": "L1.R3.echo-2-multicase",
        "summary": "The same echo program must pass additional cases.",
        "title": "Echo two bytes · multiple cases"
      },
      "rank": 6,
      "rung_digest": "c85cdc2ad0fd2b52",
      "verification": {
        "detail": "Fixed public examples, with exact output and halt required. Canonical copying solutions may be more general than the tested suite; the suite alone does not establish that.",
        "label": "Public example suite",
        "score_unit": "cases in worst epoch"
      }
    },
    {
      "placement": {
        "band": "foundations",
        "calibration": "baseline",
        "rationale": "Verified canonical or tool baseline. Similar slots are retained for historical continuity.",
        "rung_id": "L1.R2.echo-4",
        "summary": "Extend fixed-width copying to four bytes.",
        "title": "Echo four bytes"
      },
      "rank": 7,
      "rung_digest": "9e7b46fe6472c010",
      "verification": {
        "detail": "Fixed public examples, with exact output and halt required. Canonical copying solutions may be more general than the tested suite; the suite alone does not establish that.",
        "label": "Public example suite",
        "score_unit": "cases in worst epoch"
      }
    },
    {
      "placement": {
        "band": "construction",
        "calibration": "provisional",
        "rationale": "Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication.",
        "rung_id": "L2.FM0.xor51-map2",
        "summary": "Map two published input bytes to their XOR targets.",
        "title": "XOR map · 2 inputs"
      },
      "rank": 8,
      "rung_digest": "8ec6ebbc1d92e626",
      "verification": {
        "detail": "Every listed one-byte input is tested. This is the complete finite-map domain.",
        "label": "2 fixed inputs",
        "score_unit": "listed inputs"
      }
    },
    {
      "placement": {
        "band": "construction",
        "calibration": "provisional",
        "rationale": "Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication.",
        "rung_id": "L2.FM1.xor51-map4",
        "summary": "Route four published inputs to distinct answers.",
        "title": "XOR map · 4 inputs"
      },
      "rank": 9,
      "rung_digest": "9a9a74ca909f1426",
      "verification": {
        "detail": "Every listed one-byte input is tested. This is the complete finite-map domain.",
        "label": "4 fixed inputs",
        "score_unit": "listed inputs"
      }
    },
    {
      "placement": {
        "band": "construction",
        "calibration": "provisional",
        "rationale": "Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication.",
        "rung_id": "L2.R0c.crazy-mask-1",
        "summary": "Apply the machine’s crazy operation with a fixed mask.",
        "title": "Native ternary transform"
      },
      "rank": 10,
      "rung_digest": "02883eda8911be8b",
      "verification": {
        "detail": "Every first-byte value is tested for each of 1 cases over 256 epochs. The remaining input bytes are public deterministic samples. This does not exhaust all input strings or prove suffix independence.",
        "label": "256-value first-byte sweep",
        "score_unit": "cases across the sweep"
      }
    },
    {
      "placement": {
        "band": "construction",
        "calibration": "provisional",
        "rationale": "Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication.",
        "rung_id": "L3.R0.reverse-2-multicase",
        "summary": "Remember two input bytes and emit them in reverse order.",
        "title": "Reverse two bytes"
      },
      "rank": 11,
      "rung_digest": "6551e0e57ee220c8",
      "verification": {
        "detail": "Every first-byte value is tested for each of 3 cases over 256 epochs. The remaining input bytes are public deterministic samples. This does not exhaust all input strings or all multi-byte tuples.",
        "label": "256-value first-byte sweep",
        "score_unit": "cases across the sweep"
      }
    },
    {
      "placement": {
        "band": "construction",
        "calibration": "provisional",
        "rationale": "Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication.",
        "rung_id": "L2.FM1b.xor51-map6",
        "summary": "Expand input-dependent routing to six published inputs.",
        "title": "XOR map · 6 inputs"
      },
      "rank": 12,
      "rung_digest": "0d662bf44ba838e6",
      "verification": {
        "detail": "Every listed one-byte input is tested. This is the complete finite-map domain.",
        "label": "6 fixed inputs",
        "score_unit": "listed inputs"
      }
    },
    {
      "placement": {
        "band": "construction",
        "calibration": "provisional",
        "rationale": "Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication.",
        "rung_id": "L2.FM1c.xor51-map7a",
        "summary": "Add a seventh input to the six-input map.",
        "title": "XOR map · 7 inputs A"
      },
      "rank": 13,
      "rung_digest": "decbe6458d47368e",
      "verification": {
        "detail": "Every listed one-byte input is tested. This is the complete finite-map domain.",
        "label": "7 fixed inputs",
        "score_unit": "listed inputs"
      }
    },
    {
      "placement": {
        "band": "construction",
        "calibration": "provisional",
        "rationale": "Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication.",
        "rung_id": "L2.FM1d.xor51-map7b",
        "summary": "A different seventh input crowds the known routing layouts.",
        "title": "XOR map · 7 inputs B"
      },
      "rank": 14,
      "rung_digest": "57da676dd263063f",
      "verification": {
        "detail": "Every listed one-byte input is tested. This is the complete finite-map domain.",
        "label": "7 fixed inputs",
        "score_unit": "listed inputs"
      }
    },
    {
      "placement": {
        "band": "construction",
        "calibration": "provisional",
        "rationale": "Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication.",
        "rung_id": "L2.FM2.xor51-map8",
        "summary": "Fit the full eight-input routing construction.",
        "title": "XOR map · 8 inputs"
      },
      "rank": 15,
      "rung_digest": "bdc971da565c024a",
      "verification": {
        "detail": "Every listed one-byte input is tested. This is the complete finite-map domain.",
        "label": "8 fixed inputs",
        "score_unit": "listed inputs"
      }
    },
    {
      "placement": {
        "band": "construction",
        "calibration": "provisional",
        "rationale": "Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication.",
        "rung_id": "L4.R0.hash-prefix-1",
        "summary": "Fit five public input/target rows; one output byte per row.",
        "title": "Public lookup · 5 rows"
      },
      "rank": 16,
      "rung_digest": "b370a2e739a1b155",
      "verification": {
        "detail": "Fixed public inputs and target bytes. Targets depend on a seed the program does not receive. Passing measures finite lookup construction, not hash computation. The attempt score reports the worst epoch; all epochs must pass.",
        "label": "5 public lookup rows",
        "score_unit": "cases in worst epoch"
      }
    },
    {
      "placement": {
        "band": "construction",
        "calibration": "provisional",
        "rationale": "Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication.",
        "rung_id": "L4.R1.hash-prefix-1-multicase",
        "summary": "Fit fifteen public rows within 1,024 bytes.",
        "title": "Public lookup · 15 rows"
      },
      "rank": 17,
      "rung_digest": "c62ce250d64f4888",
      "verification": {
        "detail": "Fixed public inputs and target bytes. Targets depend on a seed the program does not receive. Passing measures finite lookup construction, not hash computation. The attempt score reports the worst epoch; all epochs must pass.",
        "label": "15 public lookup rows",
        "score_unit": "cases in worst epoch"
      }
    },
    {
      "placement": {
        "band": "construction",
        "calibration": "provisional",
        "rationale": "Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication.",
        "rung_id": "L4.R2.hash-prefix-length-pressure",
        "summary": "Fit ten public rows under a much tighter size limit.",
        "title": "Public lookup · 10 rows / 256 bytes"
      },
      "rank": 18,
      "rung_digest": "d682ec8b9d09f40b",
      "verification": {
        "detail": "Fixed public inputs and target bytes. Targets depend on a seed the program does not receive. Passing measures finite lookup construction, not hash computation. The attempt score reports the worst epoch; all epochs must pass.",
        "label": "10 public lookup rows",
        "score_unit": "cases in worst epoch"
      }
    },
    {
      "placement": {
        "band": "construction",
        "calibration": "provisional",
        "rationale": "Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication.",
        "rung_id": "L2.FM2h.xor51-map12-hi",
        "summary": "Route twelve published inputs from the high byte range.",
        "title": "XOR map · 12 high inputs"
      },
      "rank": 19,
      "rung_digest": "ffcb12a92e4cd638",
      "verification": {
        "detail": "Every listed one-byte input is tested. This is the complete finite-map domain.",
        "label": "12 fixed inputs",
        "score_unit": "listed inputs"
      }
    },
    {
      "placement": {
        "band": "construction",
        "calibration": "provisional",
        "rationale": "Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication.",
        "rung_id": "L2.FM2l.xor51-map12-low",
        "summary": "Route twelve published low inputs with crowded landing addresses.",
        "title": "XOR map · 12 low inputs"
      },
      "rank": 20,
      "rung_digest": "71c2bd452023ff18",
      "verification": {
        "detail": "Every listed one-byte input is tested. This is the complete finite-map domain.",
        "label": "12 fixed inputs",
        "score_unit": "listed inputs"
      }
    },
    {
      "placement": {
        "band": "construction",
        "calibration": "provisional",
        "rationale": "Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication.",
        "rung_id": "L2.FM3.xor51-map16",
        "summary": "Scale the finite map to sixteen published input bytes.",
        "title": "XOR map · 16 inputs"
      },
      "rank": 21,
      "rung_digest": "60020fe9464dec42",
      "verification": {
        "detail": "Every listed one-byte input is tested. This is the complete finite-map domain.",
        "label": "16 fixed inputs",
        "score_unit": "listed inputs"
      }
    },
    {
      "placement": {
        "band": "construction",
        "calibration": "provisional",
        "rationale": "Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication.",
        "rung_id": "L5.R1.future-hash-prefix",
        "summary": "Fit twenty public rows, producing two target bytes per row.",
        "title": "Public lookup · 20 rows / two-byte outputs"
      },
      "rank": 22,
      "rung_digest": "72fcf5bd3a607d12",
      "verification": {
        "detail": "Fixed public inputs and target bytes. Targets depend on a seed the program does not receive. Passing measures finite lookup construction, not hash computation. The attempt score reports the worst epoch; all epochs must pass.",
        "label": "20 public lookup rows",
        "score_unit": "cases in worst epoch"
      }
    },
    {
      "placement": {
        "band": "coverage",
        "calibration": "provisional",
        "rationale": "Coverage thresholds are nested only when resource limits match. The 2,048- and 8,192-byte variants add a separate size dimension. Shared solutions are correlated evidence.",
        "rung_id": "L2.C0.xor51-cov32",
        "summary": "Raise correct-byte coverage within the stated program budget.",
        "title": "XOR coverage · 32 of 256"
      },
      "rank": 23,
      "rung_digest": "2bcea61abe0c241c",
      "verification": {
        "detail": "Every one-byte input is tested; at least 32 exact outputs with a clean halt are required. Other inputs may fail.",
        "label": "All 256 input bytes",
        "score_unit": "input bytes"
      }
    },
    {
      "placement": {
        "band": "coverage",
        "calibration": "provisional",
        "rationale": "Coverage thresholds are nested only when resource limits match. The 2,048- and 8,192-byte variants add a separate size dimension. Shared solutions are correlated evidence.",
        "rung_id": "L2.C0a.xor51-cov34",
        "summary": "Raise correct-byte coverage within the stated program budget.",
        "title": "XOR coverage · 34 of 256"
      },
      "rank": 24,
      "rung_digest": "e58e020ac62c26c2",
      "verification": {
        "detail": "Every one-byte input is tested; at least 34 exact outputs with a clean halt are required. Other inputs may fail.",
        "label": "All 256 input bytes",
        "score_unit": "input bytes"
      }
    },
    {
      "placement": {
        "band": "coverage",
        "calibration": "provisional",
        "rationale": "Coverage thresholds are nested only when resource limits match. The 2,048- and 8,192-byte variants add a separate size dimension. Shared solutions are correlated evidence.",
        "rung_id": "L2.C0b.xor51-cov36",
        "summary": "Raise correct-byte coverage within the stated program budget.",
        "title": "XOR coverage · 36 of 256"
      },
      "rank": 25,
      "rung_digest": "22e256c7aefa7146",
      "verification": {
        "detail": "Every one-byte input is tested; at least 36 exact outputs with a clean halt are required. Other inputs may fail.",
        "label": "All 256 input bytes",
        "score_unit": "input bytes"
      }
    },
    {
      "placement": {
        "band": "coverage",
        "calibration": "provisional",
        "rationale": "Coverage thresholds are nested only when resource limits match. The 2,048- and 8,192-byte variants add a separate size dimension. Shared solutions are correlated evidence.",
        "rung_id": "L2.C0c.xor51-cov40",
        "summary": "Raise correct-byte coverage within the stated program budget.",
        "title": "XOR coverage · 40 of 256"
      },
      "rank": 26,
      "rung_digest": "47ecf6b4b43d1ade",
      "verification": {
        "detail": "Every one-byte input is tested; at least 40 exact outputs with a clean halt are required. Other inputs may fail.",
        "label": "All 256 input bytes",
        "score_unit": "input bytes"
      }
    },
    {
      "placement": {
        "band": "coverage",
        "calibration": "provisional",
        "rationale": "Coverage thresholds are nested only when resource limits match. The 2,048- and 8,192-byte variants add a separate size dimension. Shared solutions are correlated evidence.",
        "rung_id": "L2.C0d.xor51-cov48",
        "summary": "Raise correct-byte coverage within the stated program budget.",
        "title": "XOR coverage · 48 of 256"
      },
      "rank": 27,
      "rung_digest": "d8ae9bd82571390e",
      "verification": {
        "detail": "Every one-byte input is tested; at least 48 exact outputs with a clean halt are required. Other inputs may fail.",
        "label": "All 256 input bytes",
        "score_unit": "input bytes"
      }
    },
    {
      "placement": {
        "band": "coverage",
        "calibration": "provisional",
        "rationale": "Coverage thresholds are nested only when resource limits match. The 2,048- and 8,192-byte variants add a separate size dimension. Shared solutions are correlated evidence.",
        "rung_id": "L2.C1.xor51-cov64",
        "summary": "Raise correct-byte coverage within the stated program budget.",
        "title": "XOR coverage · 64 of 256"
      },
      "rank": 28,
      "rung_digest": "ee06c7722d4c5195",
      "verification": {
        "detail": "Every one-byte input is tested; at least 64 exact outputs with a clean halt are required. Other inputs may fail.",
        "label": "All 256 input bytes",
        "score_unit": "input bytes"
      }
    },
    {
      "placement": {
        "band": "coverage",
        "calibration": "provisional",
        "rationale": "Coverage thresholds are nested only when resource limits match. The 2,048- and 8,192-byte variants add a separate size dimension. Shared solutions are correlated evidence.",
        "rung_id": "L2.C0e.xor51-cov48-len2048",
        "summary": "Raise correct-byte coverage within the stated program budget.",
        "title": "XOR coverage · 48 / 2,048 bytes"
      },
      "rank": 29,
      "rung_digest": "3e26408718f8a5a7",
      "verification": {
        "detail": "Every one-byte input is tested; at least 48 exact outputs with a clean halt are required. Other inputs may fail.",
        "label": "All 256 input bytes",
        "score_unit": "input bytes"
      }
    },
    {
      "placement": {
        "band": "coverage",
        "calibration": "provisional",
        "rationale": "Coverage thresholds are nested only when resource limits match. The 2,048- and 8,192-byte variants add a separate size dimension. Shared solutions are correlated evidence.",
        "rung_id": "L2.C2.xor51-cov96",
        "summary": "Raise correct-byte coverage within the stated program budget.",
        "title": "XOR coverage · 96 of 256"
      },
      "rank": 30,
      "rung_digest": "bb5ec31234bdb6e2",
      "verification": {
        "detail": "Every one-byte input is tested; at least 96 exact outputs with a clean halt are required. Other inputs may fail.",
        "label": "All 256 input bytes",
        "score_unit": "input bytes"
      }
    },
    {
      "placement": {
        "band": "coverage",
        "calibration": "provisional",
        "rationale": "Coverage thresholds are nested only when resource limits match. The 2,048- and 8,192-byte variants add a separate size dimension. Shared solutions are correlated evidence.",
        "rung_id": "L2.R0d.xor-1-len4096",
        "summary": "Produce XOR 0x51 for every first-byte value.",
        "title": "Full XOR · 4,096 bytes"
      },
      "rank": 31,
      "rung_digest": "7f8bbf334a65d3d6",
      "verification": {
        "detail": "Every first-byte value is tested for each of 1 cases over 256 epochs. The remaining input bytes are public deterministic samples. This does not exhaust all input strings or prove suffix independence.",
        "label": "256-value first-byte sweep",
        "score_unit": "cases across the sweep"
      }
    },
    {
      "placement": {
        "band": "compact",
        "calibration": "nested-limit",
        "rationale": "New, uncalibrated milestone. A program passing a tighter XOR size cap also passes every looser cap with the same input sweep and step limit.",
        "rung_id": "L2.X2048.xor-1-len2048",
        "summary": "Fit full single-byte XOR in 2,048 bytes.",
        "title": "Full XOR · 2,048 bytes"
      },
      "rank": 32,
      "rung_digest": "c20fdcf58bfaaab5",
      "verification": {
        "detail": "Every first-byte value is tested for each of 1 cases over 256 epochs. The remaining input bytes are public deterministic samples. This does not exhaust all input strings or prove suffix independence.",
        "label": "256-value first-byte sweep",
        "score_unit": "cases across the sweep"
      }
    },
    {
      "placement": {
        "band": "compact",
        "calibration": "nested-limit",
        "rationale": "New, uncalibrated milestone. A program passing a tighter XOR size cap also passes every looser cap with the same input sweep and step limit.",
        "rung_id": "L2.X1024.xor-1-len1024",
        "summary": "Fit full single-byte XOR in 1,024 bytes.",
        "title": "Full XOR · 1,024 bytes"
      },
      "rank": 33,
      "rung_digest": "39d8f67d7b0fb1d5",
      "verification": {
        "detail": "Every first-byte value is tested for each of 1 cases over 256 epochs. The remaining input bytes are public deterministic samples. This does not exhaust all input strings or prove suffix independence.",
        "label": "256-value first-byte sweep",
        "score_unit": "cases across the sweep"
      }
    },
    {
      "placement": {
        "band": "compact",
        "calibration": "nested-limit",
        "rationale": "New, uncalibrated milestone. A program passing a tighter XOR size cap also passes every looser cap with the same input sweep and step limit.",
        "rung_id": "L2.X512.xor-1-len512",
        "summary": "Fit full single-byte XOR in 512 bytes.",
        "title": "Full XOR · 512 bytes"
      },
      "rank": 34,
      "rung_digest": "d990650f7cd5ebe2",
      "verification": {
        "detail": "Every first-byte value is tested for each of 1 cases over 256 epochs. The remaining input bytes are public deterministic samples. This does not exhaust all input strings or prove suffix independence.",
        "label": "256-value first-byte sweep",
        "score_unit": "cases across the sweep"
      }
    },
    {
      "placement": {
        "band": "compact",
        "calibration": "provisional",
        "rationale": "Adjacent to compact XOR based on the September 5 attempts. Scores 62/256 and 68/256 are native observations, not comparative difficulty ratings or general ceilings.",
        "rung_id": "L2.R2.rotate-1",
        "summary": "Rotate an input byte left by one binary bit.",
        "title": "Rotate one byte · 256 bytes"
      },
      "rank": 35,
      "rung_digest": "c7fef43755234b4b",
      "verification": {
        "detail": "Every first-byte value is tested for each of 1 cases over 256 epochs. The remaining input bytes are public deterministic samples. This does not exhaust all input strings or prove suffix independence.",
        "label": "256-value first-byte sweep",
        "score_unit": "cases across the sweep"
      }
    },
    {
      "placement": {
        "band": "compact",
        "calibration": "nested-limit",
        "rationale": "Tightest XOR compression milestone. The verified partial candidate is a lower bound on achievable coverage; family-specific bounds do not establish global impossibility.",
        "rung_id": "L2.R0.xor-1",
        "summary": "Fit the complete byte transform in just 256 bytes.",
        "title": "Full XOR · 256 bytes"
      },
      "rank": 36,
      "rung_digest": "de4d321c831e5840",
      "verification": {
        "detail": "Every first-byte value is tested for each of 1 cases over 256 epochs. The remaining input bytes are public deterministic samples. This does not exhaust all input strings or prove suffix independence.",
        "label": "256-value first-byte sweep",
        "score_unit": "cases across the sweep"
      }
    },
    {
      "placement": {
        "band": "multibyte",
        "calibration": "provisional",
        "rationale": "Provisional placement: width and program limits both vary. The interrupted September 5 campaign supplies no completed new result for this rung. A failed single-byte attempt is not an impossibility proof for this task.",
        "rung_id": "L3.R2.mixed-transform-small",
        "summary": "Swap the high and low four-bit halves of each of two bytes.",
        "title": "Swap nibbles · two bytes"
      },
      "rank": 37,
      "rung_digest": "ad3e3723b02b00b2",
      "verification": {
        "detail": "Every first-byte value is tested for each of 3 cases over 256 epochs. The remaining input bytes are public deterministic samples. This does not exhaust all input strings or all multi-byte tuples.",
        "label": "256-value first-byte sweep",
        "score_unit": "cases across the sweep"
      }
    },
    {
      "placement": {
        "band": "multibyte",
        "calibration": "provisional",
        "rationale": "Provisional placement: width and program limits both vary. The interrupted September 5 campaign supplies no completed new result for this rung. A failed single-byte attempt is not an impossibility proof for this task.",
        "rung_id": "L2.R3.xor-2-multicase",
        "summary": "Transform two input bytes and emit both results.",
        "title": "XOR two bytes · 384 bytes"
      },
      "rank": 38,
      "rung_digest": "9c7973e0c69b573f",
      "verification": {
        "detail": "Every first-byte value is tested for each of 2 cases over 256 epochs. The remaining input bytes are public deterministic samples. This does not exhaust all input strings or all multi-byte tuples.",
        "label": "256-value first-byte sweep",
        "score_unit": "cases across the sweep"
      }
    },
    {
      "placement": {
        "band": "multibyte",
        "calibration": "provisional",
        "rationale": "Provisional placement: width and program limits both vary. The interrupted September 5 campaign supplies no completed new result for this rung. A failed single-byte attempt is not an impossibility proof for this task.",
        "rung_id": "L5.R0.future-transform",
        "summary": "Extend nibble swapping to four bytes within 1,024 bytes of code.",
        "title": "Swap nibbles · four bytes"
      },
      "rank": 39,
      "rung_digest": "cac40482a0d89cdb",
      "verification": {
        "detail": "Every first-byte value is tested for each of 4 cases over 256 epochs. The remaining input bytes are public deterministic samples. This does not exhaust all input strings or all multi-byte tuples.",
        "label": "256-value first-byte sweep",
        "score_unit": "cases across the sweep"
      }
    },
    {
      "placement": {
        "band": "multibyte",
        "calibration": "provisional",
        "rationale": "Provisional placement: width and program limits both vary. The interrupted September 5 campaign supplies no completed new result for this rung. A failed single-byte attempt is not an impossibility proof for this task.",
        "rung_id": "L3.R1.xor-4-length-cap",
        "summary": "Transform four bytes within the tightest source budget.",
        "title": "XOR four bytes · 256 bytes"
      },
      "rank": 40,
      "rung_digest": "f91f2691b47434cd",
      "verification": {
        "detail": "Every first-byte value is tested for each of 2 cases over 256 epochs. The remaining input bytes are public deterministic samples. This does not exhaust all input strings or all multi-byte tuples.",
        "label": "256-value first-byte sweep",
        "score_unit": "cases across the sweep"
      }
    },
    {
      "placement": {
        "band": "streams",
        "calibration": "provisional",
        "rationale": "Provisional capability order: copying, counting, accumulation, and storage. The fixed public 81-case suite is evidence of behavior on those cases; it does not prove a loop or arbitrary-length correctness.",
        "rung_id": "L6.S0.cat",
        "summary": "Copy the entire input and halt when it ends.",
        "title": "Echo until EOF"
      },
      "rank": 41,
      "rung_digest": "c2366ea80a96a719",
      "verification": {
        "detail": "Public deterministic inputs of 1–255 bytes. Exact whole-output match and halt are required. Passing does not establish unseen-length generalization or prove iteration. The attempt score reports the worst epoch.",
        "label": "81 public stream cases",
        "score_unit": "cases in worst epoch"
      }
    },
    {
      "placement": {
        "band": "streams",
        "calibration": "provisional",
        "rationale": "Provisional capability order: copying, counting, accumulation, and storage. The fixed public 81-case suite is evidence of behavior on those cases; it does not prove a loop or arbitrary-length correctness.",
        "rung_id": "L6.S1.length",
        "summary": "Emit the input length as one byte, then halt.",
        "title": "Count the input bytes"
      },
      "rank": 42,
      "rung_digest": "62f49dc2ff3f7801",
      "verification": {
        "detail": "Public deterministic inputs of 1–255 bytes. Exact whole-output match and halt are required. Passing does not establish unseen-length generalization or prove iteration. The attempt score reports the worst epoch.",
        "label": "81 public stream cases",
        "score_unit": "cases in worst epoch"
      }
    },
    {
      "placement": {
        "band": "streams",
        "calibration": "provisional",
        "rationale": "Provisional capability order: copying, counting, accumulation, and storage. The fixed public 81-case suite is evidence of behavior on those cases; it does not prove a loop or arbitrary-length correctness.",
        "rung_id": "L6.S2.checksum",
        "summary": "Emit the sum modulo 256, then halt.",
        "title": "Sum the input bytes"
      },
      "rank": 43,
      "rung_digest": "e30ff0fac60abe6b",
      "verification": {
        "detail": "Public deterministic inputs of 1–255 bytes. Exact whole-output match and halt are required. Passing does not establish unseen-length generalization or prove iteration. The attempt score reports the worst epoch.",
        "label": "81 public stream cases",
        "score_unit": "cases in worst epoch"
      }
    },
    {
      "placement": {
        "band": "streams",
        "calibration": "provisional",
        "rationale": "Provisional capability order: copying, counting, accumulation, and storage. The fixed public 81-case suite is evidence of behavior on those cases; it does not prove a loop or arbitrary-length correctness.",
        "rung_id": "L6.S3.reverse",
        "summary": "Store the input and emit it backwards, then halt.",
        "title": "Reverse the entire input"
      },
      "rank": 44,
      "rung_digest": "032f1578809799e3",
      "verification": {
        "detail": "Public deterministic inputs of 1–255 bytes. Exact whole-output match and halt are required. Passing does not establish unseen-length generalization or prove iteration. The attempt score reports the worst epoch.",
        "label": "81 public stream cases",
        "score_unit": "cases in worst epoch"
      }
    }
  ],
  "schema": "malbolge-rungs.ladder.v1"
}