{"abstract":"An octave to a compound octave by a leap in one voice while the other holds (C5/C4 to C6/C4) is flagged as parallel.","category":"Music interval and transposition theory","checks":8,"contract":"Input [upper, lower], equal-length lists of MIDI pitches. For each adjacent pair of positions i, i+1 report [i, \"P5\"] or [i, \"P8\"] when the interval (upper - lower) mod 12 is 7 or 0 at both positions (the same class), both voices move (no repeated note in either), and they move in the same direction. Return the list in order; unequal lengths return None.","contract_signature":"x","evaluation_group":"w2-music-interval-parallel-perfects","failed_approach":"Excluding only a held upper voice still flags motion where the lower voice holds.","family":"w2-music-interval-parallel-perfects-oblique-motion","id":"FA-81206","implementations":{"attempt":{"sha256":"e214c9ec3e591697a252c3609bfe5a437de0dfa840b6fdb95d428a9eeb6a3f89","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    if not isinstance(x, list) or len(x) != 2:\n        return None\n    up, lo = x\n    if len(up) != len(lo):\n        return None\n    out = []\n    for i in range(len(up) - 1):\n        a = (up[i] - lo[i]) % 12\n        b = (up[i + 1] - lo[i + 1]) % 12\n        mu = up[i + 1] - up[i]\n        ml = lo[i + 1] - lo[i]\n        if a != b or a not in (0, 7):\n            continue\n        if mu == 0:\n            continue\n        if (mu > 0) != (ml > 0):\n            continue\n        out.append([i, 'P8' if a == 0 else 'P5'])\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[([[67, 69], [60, 62]], [[0, 'P5']]), ([[72, 74], [60, 62]], [[0, 'P8']]), ([[79, 81], [60, 62]], [[0, 'P5']]), ([[67, 67], [60, 60]], []), ([[67, 69], [60, 60]], []), ([[72, 67], [60, 72]], []), ([[72, 79], [60, 55]], []), ([[84, 72], [60, 60]], [])], [([[67, 67], [60, 60]], []), ([[67, 69], [60, 60]], []), ([[72, 67], [60, 72]], []), ([[72, 79], [60, 55]], []), ([[67, 72], [60, 65]], [[0, 'P5']]), ([[72, 79], [60, 60]], []), ([[60, 62], [67, 69]], []), ([[84, 72], [60, 60]], [])], [([[72, 79], [60, 55]], []), ([[67, 72], [60, 65]], [[0, 'P5']]), ([[72, 79], [60, 60]], []), ([[60, 62], [67, 69]], []), ([[55, 57], [60, 62]], [[0, 'P5']]), ([[67, 69, 71], [60, 62, 64]], [[0, 'P5'], [1, 'P5']]), ([[67, 65], [60, 58]], [[0, 'P5']]), ([[84, 72], [60, 60]], [])], [([[60, 62], [67, 69]], []), ([[55, 57], [60, 62]], [[0, 'P5']]), ([[67, 69, 71], [60, 62, 64]], [[0, 'P5'], [1, 'P5']]), ([[67, 65], [60, 58]], [[0, 'P5']]), ([[72, 72, 74], [60, 60, 62]], [[1, 'P8']]), ([[67, 72], [60, 60]], []), ([[64, 65], [60, 62]], []), ([[84, 72], [60, 60]], [])], [([[67, 65], [60, 58]], [[0, 'P5']]), ([[72, 72, 74], [60, 60, 62]], [[1, 'P8']]), ([[67, 72], [60, 60]], []), ([[64, 65], [60, 62]], []), ([[67], [60]], []), ([[], []], []), ([[67, 69], [60]], None), ([[84, 72], [60, 60]], [])]]\nfor i, (args, expected) in enumerate(fixtures[N-1]):\n    check(\"oracle %d\" % i, solve(args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"a3dac1aeafcb5da535dd36b4cbbb6d64a83e700c28ed2b5f6262c1087fb94077","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    if not isinstance(x, list) or len(x) != 2:\n        return None\n    up, lo = x\n    if len(up) != len(lo):\n        return None\n    out = []\n    for i in range(len(up) - 1):\n        a = (up[i] - lo[i]) % 12\n        b = (up[i + 1] - lo[i + 1]) % 12\n        mu = up[i + 1] - up[i]\n        ml = lo[i + 1] - lo[i]\n        if a != b or a not in (0, 7):\n            continue\n        if mu == 0 and ml == 0:\n            continue\n        if (mu > 0) != (ml > 0):\n            continue\n        out.append([i, 'P8' if a == 0 else 'P5'])\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[([[67, 69], [60, 62]], [[0, 'P5']]), ([[72, 74], [60, 62]], [[0, 'P8']]), ([[79, 81], [60, 62]], [[0, 'P5']]), ([[67, 67], [60, 60]], []), ([[67, 69], [60, 60]], []), ([[72, 67], [60, 72]], []), ([[72, 79], [60, 55]], []), ([[84, 72], [60, 60]], [])], [([[67, 67], [60, 60]], []), ([[67, 69], [60, 60]], []), ([[72, 67], [60, 72]], []), ([[72, 79], [60, 55]], []), ([[67, 72], [60, 65]], [[0, 'P5']]), ([[72, 79], [60, 60]], []), ([[60, 62], [67, 69]], []), ([[84, 72], [60, 60]], [])], [([[72, 79], [60, 55]], []), ([[67, 72], [60, 65]], [[0, 'P5']]), ([[72, 79], [60, 60]], []), ([[60, 62], [67, 69]], []), ([[55, 57], [60, 62]], [[0, 'P5']]), ([[67, 69, 71], [60, 62, 64]], [[0, 'P5'], [1, 'P5']]), ([[67, 65], [60, 58]], [[0, 'P5']]), ([[84, 72], [60, 60]], [])], [([[60, 62], [67, 69]], []), ([[55, 57], [60, 62]], [[0, 'P5']]), ([[67, 69, 71], [60, 62, 64]], [[0, 'P5'], [1, 'P5']]), ([[67, 65], [60, 58]], [[0, 'P5']]), ([[72, 72, 74], [60, 60, 62]], [[1, 'P8']]), ([[67, 72], [60, 60]], []), ([[64, 65], [60, 62]], []), ([[84, 72], [60, 60]], [])], [([[67, 65], [60, 58]], [[0, 'P5']]), ([[72, 72, 74], [60, 60, 62]], [[1, 'P8']]), ([[67, 72], [60, 60]], []), ([[64, 65], [60, 62]], []), ([[67], [60]], []), ([[], []], []), ([[67, 69], [60]], None), ([[84, 72], [60, 60]], [])]]\nfor i, (args, expected) in enumerate(fixtures[N-1]):\n    check(\"oracle %d\" % i, solve(args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"A deterministic bounded teaching model with a stipulated toy contract; it is not a complete music notation or theory engine. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w2-music-interval-parallel-perfects-oblique-motion","generated_at":"2026-09-29T14:50:00.840888+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Counterpoint checkers and voice-leading validators flag forbidden parallel perfect intervals.","root_cause":"Only a fully static pair of voices is excluded; motion in one voice alone still counts as parallel.","sha256":"ab06e376419a42bdb7286695c769ac7598e382f6bae6f21a57b824564fddebd7","title":"Parallel fifths and octaves between two voices: oblique motion into a perfect interval flagged · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":40.377,"exit_code":1,"observations":[{"actual":[[0,"P5"]],"check":"oracle 0","expected":[[0,"P5"]],"passed":true},{"actual":[[0,"P8"]],"check":"oracle 1","expected":[[0,"P8"]],"passed":true},{"actual":[[0,"P5"]],"check":"oracle 2","expected":[[0,"P5"]],"passed":true},{"actual":[],"check":"oracle 3","expected":[],"passed":true},{"actual":[],"check":"oracle 4","expected":[],"passed":true},{"actual":[],"check":"oracle 5","expected":[],"passed":true},{"actual":[],"check":"oracle 6","expected":[],"passed":true},{"actual":[[0,"P8"]],"check":"oracle 7","expected":[],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 0\", \"actual\": [[0, \"P5\"]], \"expected\": [[0, \"P5\"]], \"passed\": true}, {\"check\": \"oracle 1\", \"actual\": [[0, \"P8\"]], \"expected\": [[0, \"P8\"]], \"passed\": true}, {\"check\": \"oracle 2\", \"actual\": [[0, \"P5\"]], \"expected\": [[0, \"P5\"]], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 6\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [[0, \"P8\"]], \"expected\": [], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.557,"exit_code":1,"observations":[{"actual":[[0,"P5"]],"check":"oracle 0","expected":[[0,"P5"]],"passed":true},{"actual":[[0,"P8"]],"check":"oracle 1","expected":[[0,"P8"]],"passed":true},{"actual":[[0,"P5"]],"check":"oracle 2","expected":[[0,"P5"]],"passed":true},{"actual":[],"check":"oracle 3","expected":[],"passed":true},{"actual":[],"check":"oracle 4","expected":[],"passed":true},{"actual":[],"check":"oracle 5","expected":[],"passed":true},{"actual":[],"check":"oracle 6","expected":[],"passed":true},{"actual":[[0,"P8"]],"check":"oracle 7","expected":[],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 0\", \"actual\": [[0, \"P5\"]], \"expected\": [[0, \"P5\"]], \"passed\": true}, {\"check\": \"oracle 1\", \"actual\": [[0, \"P8\"]], \"expected\": [[0, \"P8\"]], \"passed\": true}, {\"check\": \"oracle 2\", \"actual\": [[0, \"P5\"]], \"expected\": [[0, \"P5\"]], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 6\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [[0, \"P8\"]], \"expected\": [], \"passed\": false}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}