FAILURE MAP
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FA-97536 / Knitting and sewing pattern grading / Open access

Pattern size selector: skirt governing zone · case 01

A skirt for a larger waist is cut at the hip size and will not close.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Skirts are sized by hip only.

VERIFIED REPAIR

Use the larger of the waist and hip sizes.

Unsuccessful approach: min() picks the smaller size, which is too tight at the other zone.

Case contract

Chart (cm) XS 80/62/86, S 86/68/92, M 92/74/98, L 100/82/106, XL 108/90/114 (bust/waist/hip). Inches convert at 2.54. A size fits a measurement when chart + 1 cm >= body; pick the smallest fitting size. top: by bust; skirt: the larger of waist size and hip size; dress: bust size and hip size, same -> that size, else "grade A to B" (bust size to hip size). No fitting size -> "out of range"; other garments -> "error: garment".

Why this case matters

Sewists choose a pattern size per body zone and grade between sizes.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
from fractions import Fraction
N = 1
observations = []
def solve(bust, waist, hip, garment, units):
    CHART = [['XS', 80, 62, 86], ['S', 86, 68, 92], ['M', 92, 74, 98], ['L', 100, 82, 106], ['XL', 108, 90, 114]]
    ORDER = [row[0] for row in CHART]
    k = Fraction(254, 100) if units == 'in' else Fraction(1)
    b, w, h = (Fraction(str(v)) * k for v in (bust, waist, hip))
    def pick(col, v):
        for row in CHART:
            if row[col] + 1 >= v:
                return row[0]
        return None
    if garment == 'top':
        s = pick(1, b)
        return s if s else 'out of range'
    if garment == 'skirt':
        a, c = pick(2, w), pick(3, h)
        if not a or not c:
            return 'out of range'
        return c
    if garment == 'dress':
        a, c = pick(1, b), pick(3, h)
        if not a or not c:
            return 'out of range'
        return a if a == c else 'grade %s to %s' % (a, c)
    return 'error: garment' 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['top within tolerance', [93, 70, 95, 'top', 'cm'], 'M'],
  ['skirt waist governs', [90, 80, 95, 'skirt', 'cm'], 'L'],
  ['dress grade', [86, 70, 104, 'dress', 'cm'], 'grade S to L'],
  ['regression: skirt governing zone', [34, 31, 34, 'skirt', 'in'], 'L'],
  ['repair check: skirt governing zone', [95, 79, 95, 'skirt', 'cm'], 'L'],
  ['generated control 1', [32, 29, 40, 'coat', 'in'], 'error: garment'],
  ['generated control 2', [89, 88, 117, 'coat', 'cm'], 'error: garment'],
  ['generated control 3', [98, 93, 91, 'skirt', 'cm'], 'out of range']],
 [['skirt waist governs', [90, 80, 95, 'skirt', 'cm'], 'L'],
  ['dress grade', [86, 70, 104, 'dress', 'cm'], 'grade S to L'],
  ['inches top', [36, 28, 38, 'top', 'in'], 'M'],
  ['regression: skirt governing zone', [109, 91, 86, 'skirt', 'cm'], 'XL'],
  ['repair check: skirt governing zone', [85, 67, 107, 'skirt', 'cm'], 'L'],
  ['generated control 1', [84, 76, 87, 'top', 'cm'], 'S'],
  ['generated control 2', [103, 79, 111, 'skirt', 'cm'], 'XL'],
  ['generated control 3', [91, 71, 105, 'skirt', 'cm'], 'L']],
 [['dress grade', [86, 70, 104, 'dress', 'cm'], 'grade S to L'],
  ['inches top', [36, 28, 38, 'top', 'in'], 'M'],
  ['out of range dress', [120, 90, 100, 'dress', 'cm'], 'out of range'],
  ['regression: skirt governing zone', [100, 72, 93, 'skirt', 'cm'], 'M'],
  ['repair check: skirt governing zone', [84, 77, 108, 'skirt', 'cm'], 'XL'],
  ['generated control 1', [111, 62, 95, 'coat', 'cm'], 'error: garment'],
  ['generated control 2', [105, 79, 114, 'top', 'cm'], 'XL'],
  ['generated control 3', [109, 63, 118, 'coat', 'cm'], 'error: garment']],
 [['inches top', [36, 28, 38, 'top', 'in'], 'M'],
  ['out of range dress', [120, 90, 100, 'dress', 'cm'], 'out of range'],
  ['top within tolerance', [93, 70, 95, 'top', 'cm'], 'M'],
  ['regression: skirt governing zone', [93, 85, 91, 'skirt', 'cm'], 'XL'],
  ['repair check: skirt governing zone', [78, 61, 109, 'skirt', 'cm'], 'XL'],
  ['generated control 1', [42.5, 34, 36, 'dress', 'in'], 'grade XL to S'],
  ['generated control 2', [79, 73, 116, 'coat', 'cm'], 'error: garment'],
  ['generated control 3', [80, 67, 118, 'skirt', 'cm'], 'out of range']],
 [['out of range dress', [120, 90, 100, 'dress', 'cm'], 'out of range'],
  ['top within tolerance', [93, 70, 95, 'top', 'cm'], 'M'],
  ['skirt waist governs', [90, 80, 95, 'skirt', 'cm'], 'L'],
  ['regression: skirt governing zone', [38, 31, 38, 'skirt', 'in'], 'L'],
  ['repair check: skirt governing zone', [34, 31, 43, 'skirt', 'in'], 'XL'],
  ['generated control 1', [87, 94, 94, 'top', 'cm'], 'S'],
  ['generated control 2', [110, 65, 112, 'coat', 'cm'], 'error: garment'],
  ['generated control 3', [85, 71, 101, 'dress', 'cm'], 'grade S to L']]]
for label, args, expected in fixtures[N - 1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
top within toleranceMMPassed
skirt waist governsMLFailed
dress gradegrade S to Lgrade S to LPassed
regression: skirt governing zoneXSLFailed
repair check: skirt governing zoneMLFailed
generated control 1error: garmenterror: garmentPassed
generated control 2error: garmenterror: garmentPassed
generated control 3out of rangeout of rangePassed

SHA-256 / 07ad9da32807d8a9f40c52538ee7fa8f8554cafe67f4752cb09e30ac02aeda3c

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
from fractions import Fraction
N = 1
observations = []
def solve(bust, waist, hip, garment, units):
    CHART = [['XS', 80, 62, 86], ['S', 86, 68, 92], ['M', 92, 74, 98], ['L', 100, 82, 106], ['XL', 108, 90, 114]]
    ORDER = [row[0] for row in CHART]
    k = Fraction(254, 100) if units == 'in' else Fraction(1)
    b, w, h = (Fraction(str(v)) * k for v in (bust, waist, hip))
    def pick(col, v):
        for row in CHART:
            if row[col] + 1 >= v:
                return row[0]
        return None
    if garment == 'top':
        s = pick(1, b)
        return s if s else 'out of range'
    if garment == 'skirt':
        a, c = pick(2, w), pick(3, h)
        if not a or not c:
            return 'out of range'
        return min(a, c, key=ORDER.index)
    if garment == 'dress':
        a, c = pick(1, b), pick(3, h)
        if not a or not c:
            return 'out of range'
        return a if a == c else 'grade %s to %s' % (a, c)
    return 'error: garment' 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['top within tolerance', [93, 70, 95, 'top', 'cm'], 'M'],
  ['skirt waist governs', [90, 80, 95, 'skirt', 'cm'], 'L'],
  ['dress grade', [86, 70, 104, 'dress', 'cm'], 'grade S to L'],
  ['regression: skirt governing zone', [34, 31, 34, 'skirt', 'in'], 'L'],
  ['repair check: skirt governing zone', [95, 79, 95, 'skirt', 'cm'], 'L'],
  ['generated control 1', [32, 29, 40, 'coat', 'in'], 'error: garment'],
  ['generated control 2', [89, 88, 117, 'coat', 'cm'], 'error: garment'],
  ['generated control 3', [98, 93, 91, 'skirt', 'cm'], 'out of range']],
 [['skirt waist governs', [90, 80, 95, 'skirt', 'cm'], 'L'],
  ['dress grade', [86, 70, 104, 'dress', 'cm'], 'grade S to L'],
  ['inches top', [36, 28, 38, 'top', 'in'], 'M'],
  ['regression: skirt governing zone', [109, 91, 86, 'skirt', 'cm'], 'XL'],
  ['repair check: skirt governing zone', [85, 67, 107, 'skirt', 'cm'], 'L'],
  ['generated control 1', [84, 76, 87, 'top', 'cm'], 'S'],
  ['generated control 2', [103, 79, 111, 'skirt', 'cm'], 'XL'],
  ['generated control 3', [91, 71, 105, 'skirt', 'cm'], 'L']],
 [['dress grade', [86, 70, 104, 'dress', 'cm'], 'grade S to L'],
  ['inches top', [36, 28, 38, 'top', 'in'], 'M'],
  ['out of range dress', [120, 90, 100, 'dress', 'cm'], 'out of range'],
  ['regression: skirt governing zone', [100, 72, 93, 'skirt', 'cm'], 'M'],
  ['repair check: skirt governing zone', [84, 77, 108, 'skirt', 'cm'], 'XL'],
  ['generated control 1', [111, 62, 95, 'coat', 'cm'], 'error: garment'],
  ['generated control 2', [105, 79, 114, 'top', 'cm'], 'XL'],
  ['generated control 3', [109, 63, 118, 'coat', 'cm'], 'error: garment']],
 [['inches top', [36, 28, 38, 'top', 'in'], 'M'],
  ['out of range dress', [120, 90, 100, 'dress', 'cm'], 'out of range'],
  ['top within tolerance', [93, 70, 95, 'top', 'cm'], 'M'],
  ['regression: skirt governing zone', [93, 85, 91, 'skirt', 'cm'], 'XL'],
  ['repair check: skirt governing zone', [78, 61, 109, 'skirt', 'cm'], 'XL'],
  ['generated control 1', [42.5, 34, 36, 'dress', 'in'], 'grade XL to S'],
  ['generated control 2', [79, 73, 116, 'coat', 'cm'], 'error: garment'],
  ['generated control 3', [80, 67, 118, 'skirt', 'cm'], 'out of range']],
 [['out of range dress', [120, 90, 100, 'dress', 'cm'], 'out of range'],
  ['top within tolerance', [93, 70, 95, 'top', 'cm'], 'M'],
  ['skirt waist governs', [90, 80, 95, 'skirt', 'cm'], 'L'],
  ['regression: skirt governing zone', [38, 31, 38, 'skirt', 'in'], 'L'],
  ['repair check: skirt governing zone', [34, 31, 43, 'skirt', 'in'], 'XL'],
  ['generated control 1', [87, 94, 94, 'top', 'cm'], 'S'],
  ['generated control 2', [110, 65, 112, 'coat', 'cm'], 'error: garment'],
  ['generated control 3', [85, 71, 101, 'dress', 'cm'], 'grade S to L']]]
for label, args, expected in fixtures[N - 1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
top within toleranceMMPassed
skirt waist governsMLFailed
dress gradegrade S to Lgrade S to LPassed
regression: skirt governing zoneXSLFailed
repair check: skirt governing zoneMLFailed
generated control 1error: garmenterror: garmentPassed
generated control 2error: garmenterror: garmentPassed
generated control 3out of rangeout of rangePassed

SHA-256 / 1b9cb9f936e376bce50b5536101013c48bcbe4f9737d1559c45f037f56b5957d

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json
import math
from fractions import Fraction
N = 1
observations = []
def solve(bust, waist, hip, garment, units):
    CHART = [['XS', 80, 62, 86], ['S', 86, 68, 92], ['M', 92, 74, 98], ['L', 100, 82, 106], ['XL', 108, 90, 114]]
    ORDER = [row[0] for row in CHART]
    k = Fraction(254, 100) if units == 'in' else Fraction(1)
    b, w, h = (Fraction(str(v)) * k for v in (bust, waist, hip))
    def pick(col, v):
        for row in CHART:
            if row[col] + 1 >= v:
                return row[0]
        return None
    if garment == 'top':
        s = pick(1, b)
        return s if s else 'out of range'
    if garment == 'skirt':
        a, c = pick(2, w), pick(3, h)
        if not a or not c:
            return 'out of range'
        return max(a, c, key=ORDER.index)
    if garment == 'dress':
        a, c = pick(1, b), pick(3, h)
        if not a or not c:
            return 'out of range'
        return a if a == c else 'grade %s to %s' % (a, c)
    return 'error: garment' 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['top within tolerance', [93, 70, 95, 'top', 'cm'], 'M'],
  ['skirt waist governs', [90, 80, 95, 'skirt', 'cm'], 'L'],
  ['dress grade', [86, 70, 104, 'dress', 'cm'], 'grade S to L'],
  ['regression: skirt governing zone', [34, 31, 34, 'skirt', 'in'], 'L'],
  ['repair check: skirt governing zone', [95, 79, 95, 'skirt', 'cm'], 'L'],
  ['generated control 1', [32, 29, 40, 'coat', 'in'], 'error: garment'],
  ['generated control 2', [89, 88, 117, 'coat', 'cm'], 'error: garment'],
  ['generated control 3', [98, 93, 91, 'skirt', 'cm'], 'out of range']],
 [['skirt waist governs', [90, 80, 95, 'skirt', 'cm'], 'L'],
  ['dress grade', [86, 70, 104, 'dress', 'cm'], 'grade S to L'],
  ['inches top', [36, 28, 38, 'top', 'in'], 'M'],
  ['regression: skirt governing zone', [109, 91, 86, 'skirt', 'cm'], 'XL'],
  ['repair check: skirt governing zone', [85, 67, 107, 'skirt', 'cm'], 'L'],
  ['generated control 1', [84, 76, 87, 'top', 'cm'], 'S'],
  ['generated control 2', [103, 79, 111, 'skirt', 'cm'], 'XL'],
  ['generated control 3', [91, 71, 105, 'skirt', 'cm'], 'L']],
 [['dress grade', [86, 70, 104, 'dress', 'cm'], 'grade S to L'],
  ['inches top', [36, 28, 38, 'top', 'in'], 'M'],
  ['out of range dress', [120, 90, 100, 'dress', 'cm'], 'out of range'],
  ['regression: skirt governing zone', [100, 72, 93, 'skirt', 'cm'], 'M'],
  ['repair check: skirt governing zone', [84, 77, 108, 'skirt', 'cm'], 'XL'],
  ['generated control 1', [111, 62, 95, 'coat', 'cm'], 'error: garment'],
  ['generated control 2', [105, 79, 114, 'top', 'cm'], 'XL'],
  ['generated control 3', [109, 63, 118, 'coat', 'cm'], 'error: garment']],
 [['inches top', [36, 28, 38, 'top', 'in'], 'M'],
  ['out of range dress', [120, 90, 100, 'dress', 'cm'], 'out of range'],
  ['top within tolerance', [93, 70, 95, 'top', 'cm'], 'M'],
  ['regression: skirt governing zone', [93, 85, 91, 'skirt', 'cm'], 'XL'],
  ['repair check: skirt governing zone', [78, 61, 109, 'skirt', 'cm'], 'XL'],
  ['generated control 1', [42.5, 34, 36, 'dress', 'in'], 'grade XL to S'],
  ['generated control 2', [79, 73, 116, 'coat', 'cm'], 'error: garment'],
  ['generated control 3', [80, 67, 118, 'skirt', 'cm'], 'out of range']],
 [['out of range dress', [120, 90, 100, 'dress', 'cm'], 'out of range'],
  ['top within tolerance', [93, 70, 95, 'top', 'cm'], 'M'],
  ['skirt waist governs', [90, 80, 95, 'skirt', 'cm'], 'L'],
  ['regression: skirt governing zone', [38, 31, 38, 'skirt', 'in'], 'L'],
  ['repair check: skirt governing zone', [34, 31, 43, 'skirt', 'in'], 'XL'],
  ['generated control 1', [87, 94, 94, 'top', 'cm'], 'S'],
  ['generated control 2', [110, 65, 112, 'coat', 'cm'], 'error: garment'],
  ['generated control 3', [85, 71, 101, 'dress', 'cm'], 'grade S to L']]]
for label, args, expected in fixtures[N - 1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
top within toleranceMMPassed
skirt waist governsLLPassed
dress gradegrade S to Lgrade S to LPassed
regression: skirt governing zoneLLPassed
repair check: skirt governing zoneLLPassed
generated control 1error: garmenterror: garmentPassed
generated control 2error: garmenterror: garmentPassed
generated control 3out of rangeout of rangePassed

SHA-256 / daa581e5c04513d5a2ebf9a8bb186530e30f239318edaec137d726b4b5ab0393

Verification & scope

A deterministic toy contract stated in full here; it is a bounded teaching model, not an authoritative reference or standards implementation. 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.

Observations recorded using Python 3.12.14 at 2026-09-29T14:52:33.097075+00:00.

Case digest / 77cf81bc1047afb85ba295356723eae93de05c5b40f8f3a0e45423d3461830b1