{"abstract":"The triangulation has n minus two triangles, not n.","category":"Planar geometry","checks":4,"contract":"Integer coordinates and lengths, with exact arithmetic except for indicated division results. Lengths are nonnegative. Rectangles are (xmin,ymin,xmax,ymax) with ordered bounds; coordinate vectors have matching dimensions. Regular polygon interior angle sum. Exact operational definition: 180*(n-2)","contract_signature":"n","evaluation_group":"model-70989377e340821b","failed_approach":"Exterior-angle sum is confused with interior-angle sum.","family":"xn-regular-polygon-interior-angle-sum","id":"FA-5826","implementations":{"attempt":{"sha256":"6e58eeb7c2a38c8586d0fa0c63af116b99276c714801f18b9bade0764644910d","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nimport calendar\nimport statistics\nimport itertools\nfrom fractions import Fraction\nfrom datetime import date, datetime, timedelta, timezone\nfrom decimal import Decimal, ROUND_HALF_UP, ROUND_DOWN, ROUND_CEILING, ROUND_FLOOR\n\nN = 1\nobservations = []\ndef solve(n):\n    return 360\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: (3,)', solve(*(3,)), 180)\ncheck('fixture 2: (4,)', solve(*(4,)), 360)\ncheck('fixture 3: (5,)', solve(*(5,)), 540)\ncheck('fixture 4: (8,)', solve(*(8,)), 1080)\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":"63e71351cf5410a270b25a2fba4d598dea43b1eee3653b4df44be05f1e2d69d9","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nimport calendar\nimport statistics\nimport itertools\nfrom fractions import Fraction\nfrom datetime import date, datetime, timedelta, timezone\nfrom decimal import Decimal, ROUND_HALF_UP, ROUND_DOWN, ROUND_CEILING, ROUND_FLOOR\n\nN = 1\nobservations = []\ndef solve(n):\n    return 180*n\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: (3,)', solve(*(3,)), 180)\ncheck('fixture 2: (4,)', solve(*(4,)), 360)\ncheck('fixture 3: (5,)', solve(*(5,)), 540)\ncheck('fixture 4: (8,)', solve(*(8,)), 1080)\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":" 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":"xn-regular-polygon-interior-angle-sum","generated_at":"2026-09-29T14:37:54.275816+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Small exact fixtures expose this error without platform timing, external services, or probabilistic observations. Planar geometry results depend on the stated convention.","root_cause":"The triangulation has n minus two triangles, not n.","sha256":"61b348ef5275ded74ba2c0c8242023d8c4fa1d38b54376c62fb3cfd17b8127db","title":"Regular polygon interior angle sum · 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":50.488,"exit_code":1,"observations":[{"actual":360,"check":"fixture 1: (3,)","expected":180,"passed":false},{"actual":360,"check":"fixture 2: (4,)","expected":360,"passed":true},{"actual":360,"check":"fixture 3: (5,)","expected":540,"passed":false},{"actual":360,"check":"fixture 4: (8,)","expected":1080,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: (3,)\", \"actual\": 360, \"expected\": 180, \"passed\": false}, {\"check\": \"fixture 2: (4,)\", \"actual\": 360, \"expected\": 360, \"passed\": true}, {\"check\": \"fixture 3: (5,)\", \"actual\": 360, \"expected\": 540, \"passed\": false}, {\"check\": \"fixture 4: (8,)\", \"actual\": 360, \"expected\": 1080, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":49.103,"exit_code":1,"observations":[{"actual":540,"check":"fixture 1: (3,)","expected":180,"passed":false},{"actual":720,"check":"fixture 2: (4,)","expected":360,"passed":false},{"actual":900,"check":"fixture 3: (5,)","expected":540,"passed":false},{"actual":1440,"check":"fixture 4: (8,)","expected":1080,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: (3,)\", \"actual\": 540, \"expected\": 180, \"passed\": false}, {\"check\": \"fixture 2: (4,)\", \"actual\": 720, \"expected\": 360, \"passed\": false}, {\"check\": \"fixture 3: (5,)\", \"actual\": 900, \"expected\": 540, \"passed\": false}, {\"check\": \"fixture 4: (8,)\", \"actual\": 1440, \"expected\": 1080, \"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."}}