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FA-97471 / Knitting and sewing pattern grading / Open access

Knitting chart row reader: rounds have no WS · case 01

Every other round is read backwards with purls and knits swapped.

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

ROOT CAUSE

Circular knitting still alternates RS/WS handling.

THE FAILURE

Circular knitting still alternates RS/WS handling.

Unsuccessful approach: Letting start_ws re-enable flipping still breaks rounds.

Case contract

chart rows are listed bottom-up (row 1 first), cells left-to-right as drawn. Rounds and RS rows read right-to-left unchanged. Flat WS rows (even rows, or odd rows when start_ws) read left-to-right with swaps k<->p, k2tog->p2tog, ssk->ssp, yo stays. Runs of identical stitches merge: k/p as "k3", others as "yo" or "yo x2". Row outside 1..len -> error.

Why this case matters

Chart readers must flip reading direction and stitch meaning on wrong-side rows.

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(chart, row, in_round, start_ws):
    SWAP = {'k': 'p', 'p': 'k', 'k2tog': 'p2tog', 'ssk': 'ssp', 'yo': 'yo'}
    if not 1 <= row <= len(chart):
        return 'error: no such row'
    cells = list(chart[row - 1])
    ws = ((row % 2 == 0) != start_ws)
    if ws:
        seq = [SWAP.get(c, c) for c in cells]
    else:
        seq = cells[::-1]
    out = []
    for c in seq:
        if out and out[-1][0] == c:
            out[-1][1] += 1
        else:
            out.append([c, 1])
    return ', '.join(c + str(n) if c in ('k', 'p') else (c if n == 1 else '%s x%d' % (c, n)) for c, n in out)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['RS row', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'k', 'k']], 1, False, False],
   'k2tog, yo, p1, k2'],
  ['WS row swapped', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'ssk', 'k']], 2, False, False],
   'k2, p1, ssp, p1'],
  ['in the round', [[['k', 'p'], ['ssk', 'k']], 2, True, False], 'k1, ssk'],
  ['regression: rounds have no WS',
   [[['yo', 'yo', 'yo', 'yo', 'yo', 'k'], ['ssk', 'k2tog', 'p', 'k2tog', 'yo', 'yo'],
     ['k', 'p', 'k', 'yo', 'p', 'p'], ['ssk', 'k2tog', 'ssk', 'ssk', 'p', 'k2tog'],
     ['ssk', 'ssk', 'yo', 'yo', 'ssk', 'k']],
    3, True, True],
   'p2, yo, k1, p1, k1'],
  ['repair check: rounds have no WS',
   [[['k', 'k', 'yo', 'yo', 'p'], ['k2tog', 'ssk', 'yo', 'p', 'p'], ['k2tog', 'k2tog', 'ssk', 'p', 'yo']], 1,
    True, True],
   'p1, yo x2, k2'],
  ['generated control 1',
   [[['ssk', 'k2tog', 'yo', 'yo', 'k2tog', 'ssk', 'ssk', 'k2tog'],
     ['ssk', 'ssk', 'k2tog', 'k', 'ssk', 'k', 'p', 'yo'],
     ['p', 'ssk', 'ssk', 'yo', 'yo', 'k2tog', 'yo', 'k2tog'],
     ['k2tog', 'k', 'ssk', 'k2tog', 'k', 'p', 'k', 'ssk']],
    3, False, False],
   'k2tog, yo, k2tog, yo x2, ssk x2, p1'],
  ['generated control 2',
   [[['k2tog', 'yo', 'yo', 'yo'], ['p', 'k2tog', 'yo', 'k2tog'], ['k', 'k2tog', 'ssk', 'ssk'],
     ['ssk', 'p', 'p', 'k2tog'], ['k2tog', 'p', 'k', 'yo'], ['yo', 'yo', 'p', 'p']],
    3, False, False],
   'ssk x2, k2tog, k1'],
  ['generated control 3',
   [[['k2tog', 'p', 'yo', 'p', 'k2tog', 'k2tog'], ['k2tog', 'yo', 'k', 'p', 'ssk', 'yo'],
     ['p', 'p', 'yo', 'k', 'ssk', 'k'], ['yo', 'yo', 'ssk', 'p', 'k', 'ssk']],
    3, False, True],
   'k2, yo, p1, ssp, p1']],
 [['WS row swapped', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'ssk', 'k']], 2, False, False],
   'k2, p1, ssp, p1'],
  ['in the round', [[['k', 'p'], ['ssk', 'k']], 2, True, False], 'k1, ssk'],
  ['out of range', [[['k']], 3, False, False], 'error: no such row'],
  ['regression: rounds have no WS',
   [[['p', 'p', 'k', 'k2tog', 'yo', 'k2tog', 'yo', 'yo'],
     ['ssk', 'p', 'k2tog', 'k', 'k', 'ssk', 'k2tog', 'k2tog'],
     ['k', 'p', 'k', 'k2tog', 'ssk', 'p', 'k', 'k2tog'], ['k', 'k', 'yo', 'k2tog', 'k2tog', 'p', 'yo', 'k'],
     ['ssk', 'k', 'ssk', 'k2tog', 'yo', 'k2tog', 'ssk', 'k2tog'],
     ['k', 'ssk', 'ssk', 'yo', 'p', 'k2tog', 'ssk', 'k2tog']],
    3, True, True],
   'k2tog, k1, p1, ssk, k2tog, k1, p1, k1'],
  ['repair check: rounds have no WS',
   [[['p', 'k2tog', 'ssk', 'yo', 'k2tog', 'yo', 'yo'], ['yo', 'p', 'ssk', 'k', 'ssk', 'ssk', 'k2tog'],
     ['p', 'ssk', 'k2tog', 'ssk', 'p', 'ssk', 'yo']],
    3, True, True],
   'yo, ssk, p1, ssk, k2tog, ssk, p1'],
  ['generated control 1',
   [[['ssk', 'k', 'k', 'k', 'k', 'k', 'k'], ['k', 'ssk', 'yo', 'k2tog', 'k2tog', 'ssk', 'ssk'],
     ['yo', 'yo', 'p', 'yo', 'p', 'ssk', 'k']],
    1, True, False],
   'k6, ssk'],
  ['generated control 2',
   [[['k2tog', 'p', 'yo', 'yo'], ['k', 'yo', 'k2tog', 'yo'], ['ssk', 'p', 'k2tog', 'k2tog']], 1, False,
    False],
   'yo x2, p1, k2tog'],
  ['generated control 3',
   [[['ssk', 'k2tog', 'ssk', 'k2tog', 'yo'], ['ssk', 'k2tog', 'ssk', 'yo', 'ssk']], 1, False, False],
   'yo, k2tog, ssk, k2tog, ssk']],
 [['in the round', [[['k', 'p'], ['ssk', 'k']], 2, True, False], 'k1, ssk'],
  ['out of range', [[['k']], 3, False, False], 'error: no such row'],
  ['RS row', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'k', 'k']], 1, False, False],
   'k2tog, yo, p1, k2'],
  ['regression: rounds have no WS',
   [[['yo', 'yo', 'k2tog'], ['yo', 'k2tog', 'k2tog'], ['k2tog', 'p', 'k2tog'], ['k', 'ssk', 'yo'],
     ['p', 'ssk', 'k']],
    4, True, False],
   'yo, ssk, k1'],
  ['repair check: rounds have no WS',
   [[['ssk', 'ssk', 'ssk', 'k2tog'], ['p', 'p', 'k2tog', 'ssk']], 1, True, True], 'k2tog, ssk x3'],
  ['generated control 1',
   [[['k', 'ssk', 'k', 'k', 'p', 'k', 'k'], ['k2tog', 'yo', 'yo', 'yo', 'k2tog', 'ssk', 'yo'],
     ['p', 'ssk', 'p', 'ssk', 'k', 'yo', 'k']],
    3, True, False],
   'k1, yo, k1, ssk, p1, ssk, p1'],
  ['generated control 2',
   [[['yo', 'ssk', 'ssk', 'k2tog', 'k2tog'], ['p', 'yo', 'k2tog', 'k2tog', 'p'],
     ['k2tog', 'p', 'k2tog', 'k2tog', 'yo'], ['p', 'p', 'k2tog', 'k2tog', 'p']],
    1, False, False],
   'k2tog x2, ssk x2, yo'],
  ['generated control 3',
   [[['yo', 'yo', 'yo', 'k'], ['ssk', 'ssk', 'k', 'k2tog'], ['ssk', 'p', 'p', 'ssk']], 1, True, False],
   'k1, yo x3']],
 [['out of range', [[['k']], 3, False, False], 'error: no such row'],
  ['RS row', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'k', 'k']], 1, False, False],
   'k2tog, yo, p1, k2'],
  ['WS row swapped', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'ssk', 'k']], 2, False, False],
   'k2, p1, ssp, p1'],
  ['regression: rounds have no WS',
   [[['yo', 'yo', 'k', 'yo', 'yo'], ['yo', 'ssk', 'ssk', 'p', 'k'], ['k', 'k', 'p', 'p', 'yo'],
     ['k', 'ssk', 'p', 'p', 'ssk']],
    1, True, True],
   'yo x2, k1, yo x2'],
  ['repair check: rounds have no WS',
   [[['k2tog', 'yo', 'yo', 'ssk', 'ssk'], ['yo', 'k2tog', 'ssk', 'ssk', 'k'],
     ['k', 'k2tog', 'k2tog', 'k2tog', 'k2tog'], ['k2tog', 'k', 'k', 'k', 'p'],
     ['ssk', 'yo', 'k2tog', 'k', 'yo']],
    1, True, True],
   'ssk x2, yo x2, k2tog'],
  ['generated control 1',
   [[['k', 'p', 'k2tog'], ['ssk', 'k', 'k'], ['p', 'k2tog', 'k2tog'], ['k', 'k', 'k2tog'],
     ['ssk', 'k', 'k2tog'], ['p', 'yo', 'p']],
    1, False, False],
   'k2tog, p1, k1'],
  ['generated control 2',
   [[['k2tog', 'ssk', 'k', 'p', 'yo', 'yo', 'k2tog'], ['k', 'ssk', 'yo', 'k2tog', 'yo', 'p', 'k2tog'],
     ['ssk', 'ssk', 'p', 'k2tog', 'p', 'k', 'yo'], ['ssk', 'yo', 'p', 'k', 'k', 'k', 'p']],
    3, False, False],
   'yo, k1, p1, k2tog, p1, ssk x2'],
  ['generated control 3', [[['ssk', 'k', 'ssk'], ['p', 'k', 'yo']], 2, True, True], 'yo, k1, p1']],
 [['RS row', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'k', 'k']], 1, False, False],
   'k2tog, yo, p1, k2'],
  ['WS row swapped', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'ssk', 'k']], 2, False, False],
   'k2, p1, ssp, p1'],
  ['in the round', [[['k', 'p'], ['ssk', 'k']], 2, True, False], 'k1, ssk'],
  ['regression: rounds have no WS',
   [[['yo', 'yo', 'k2tog', 'yo', 'ssk', 'k'], ['k2tog', 'k', 'k2tog', 'p', 'k', 'k2tog']], 2, True, False],
   'k2tog, k1, p1, k2tog, k1, k2tog'],
  ['repair check: rounds have no WS',
   [[['yo', 'yo', 'ssk', 'k'], ['yo', 'k2tog', 'k', 'p'], ['ssk', 'ssk', 'yo', 'yo'],
     ['p', 'k2tog', 'k', 'p']],
    3, True, True],
   'yo x2, ssk x2'],
  ['generated control 1',
   [[['ssk', 'k', 'k'], ['yo', 'k', 'yo'], ['ssk', 'p', 'ssk'], ['k', 'yo', 'yo']], 2, False, False],
   'yo, p1, yo'],
  ['generated control 2',
   [[['k2tog', 'p', 'p', 'k', 'yo', 'k2tog'], ['ssk', 'k2tog', 'p', 'k', 'p', 'yo']], 1, False, False],
   'k2tog, yo, k1, p2, k2tog'],
  ['generated control 3',
   [[['yo', 'k', 'k', 'ssk', 'p', 'yo', 'yo', 'k2tog'], ['yo', 'ssk', 'k2tog', 'ssk', 'yo', 'k', 'yo', 'k'],
     ['yo', 'p', 'p', 'p', 'p', 'k', 'p', 'k'], ['yo', 'p', 'yo', 'ssk', 'k2tog', 'p', 'p', 'ssk'],
     ['p', 'p', 'yo', 'ssk', 'k', 'yo', 'k', 'yo']],
    2, False, False],
   'yo, ssp, p2tog, ssp, yo, p1, yo, p1']]]
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
RS rowk2tog, yo, p1, k2k2tog, yo, p1, k2Passed
WS row swappedk2, p1, ssp, p1k2, p1, ssp, p1Passed
in the roundssp, p1k1, sskFailed
regression: rounds have no WSp1, k1, p1, yo, k2p2, yo, k1, p1, k1Failed
repair check: rounds have no WSp2, yo x2, k1p1, yo x2, k2Failed
generated control 1k2tog, yo, k2tog, yo x2, ssk x2, p1k2tog, yo, k2tog, yo x2, ssk x2, p1Passed
generated control 2ssk x2, k2tog, k1ssk x2, k2tog, k1Passed
generated control 3k2, yo, p1, ssp, p1k2, yo, p1, ssp, p1Passed

SHA-256 / ca00d8d70a3fab57854baa951727f1855b85770c9f311f6836df292b122b026d

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(chart, row, in_round, start_ws):
    SWAP = {'k': 'p', 'p': 'k', 'k2tog': 'p2tog', 'ssk': 'ssp', 'yo': 'yo'}
    if not 1 <= row <= len(chart):
        return 'error: no such row'
    cells = list(chart[row - 1])
    ws = (not in_round or start_ws) and ((row % 2 == 0) != start_ws)
    if ws:
        seq = [SWAP.get(c, c) for c in cells]
    else:
        seq = cells[::-1]
    out = []
    for c in seq:
        if out and out[-1][0] == c:
            out[-1][1] += 1
        else:
            out.append([c, 1])
    return ', '.join(c + str(n) if c in ('k', 'p') else (c if n == 1 else '%s x%d' % (c, n)) for c, n in out)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['RS row', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'k', 'k']], 1, False, False],
   'k2tog, yo, p1, k2'],
  ['WS row swapped', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'ssk', 'k']], 2, False, False],
   'k2, p1, ssp, p1'],
  ['in the round', [[['k', 'p'], ['ssk', 'k']], 2, True, False], 'k1, ssk'],
  ['regression: rounds have no WS',
   [[['yo', 'yo', 'yo', 'yo', 'yo', 'k'], ['ssk', 'k2tog', 'p', 'k2tog', 'yo', 'yo'],
     ['k', 'p', 'k', 'yo', 'p', 'p'], ['ssk', 'k2tog', 'ssk', 'ssk', 'p', 'k2tog'],
     ['ssk', 'ssk', 'yo', 'yo', 'ssk', 'k']],
    3, True, True],
   'p2, yo, k1, p1, k1'],
  ['repair check: rounds have no WS',
   [[['k', 'k', 'yo', 'yo', 'p'], ['k2tog', 'ssk', 'yo', 'p', 'p'], ['k2tog', 'k2tog', 'ssk', 'p', 'yo']], 1,
    True, True],
   'p1, yo x2, k2'],
  ['generated control 1',
   [[['ssk', 'k2tog', 'yo', 'yo', 'k2tog', 'ssk', 'ssk', 'k2tog'],
     ['ssk', 'ssk', 'k2tog', 'k', 'ssk', 'k', 'p', 'yo'],
     ['p', 'ssk', 'ssk', 'yo', 'yo', 'k2tog', 'yo', 'k2tog'],
     ['k2tog', 'k', 'ssk', 'k2tog', 'k', 'p', 'k', 'ssk']],
    3, False, False],
   'k2tog, yo, k2tog, yo x2, ssk x2, p1'],
  ['generated control 2',
   [[['k2tog', 'yo', 'yo', 'yo'], ['p', 'k2tog', 'yo', 'k2tog'], ['k', 'k2tog', 'ssk', 'ssk'],
     ['ssk', 'p', 'p', 'k2tog'], ['k2tog', 'p', 'k', 'yo'], ['yo', 'yo', 'p', 'p']],
    3, False, False],
   'ssk x2, k2tog, k1'],
  ['generated control 3',
   [[['k2tog', 'p', 'yo', 'p', 'k2tog', 'k2tog'], ['k2tog', 'yo', 'k', 'p', 'ssk', 'yo'],
     ['p', 'p', 'yo', 'k', 'ssk', 'k'], ['yo', 'yo', 'ssk', 'p', 'k', 'ssk']],
    3, False, True],
   'k2, yo, p1, ssp, p1']],
 [['WS row swapped', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'ssk', 'k']], 2, False, False],
   'k2, p1, ssp, p1'],
  ['in the round', [[['k', 'p'], ['ssk', 'k']], 2, True, False], 'k1, ssk'],
  ['out of range', [[['k']], 3, False, False], 'error: no such row'],
  ['regression: rounds have no WS',
   [[['p', 'p', 'k', 'k2tog', 'yo', 'k2tog', 'yo', 'yo'],
     ['ssk', 'p', 'k2tog', 'k', 'k', 'ssk', 'k2tog', 'k2tog'],
     ['k', 'p', 'k', 'k2tog', 'ssk', 'p', 'k', 'k2tog'], ['k', 'k', 'yo', 'k2tog', 'k2tog', 'p', 'yo', 'k'],
     ['ssk', 'k', 'ssk', 'k2tog', 'yo', 'k2tog', 'ssk', 'k2tog'],
     ['k', 'ssk', 'ssk', 'yo', 'p', 'k2tog', 'ssk', 'k2tog']],
    3, True, True],
   'k2tog, k1, p1, ssk, k2tog, k1, p1, k1'],
  ['repair check: rounds have no WS',
   [[['p', 'k2tog', 'ssk', 'yo', 'k2tog', 'yo', 'yo'], ['yo', 'p', 'ssk', 'k', 'ssk', 'ssk', 'k2tog'],
     ['p', 'ssk', 'k2tog', 'ssk', 'p', 'ssk', 'yo']],
    3, True, True],
   'yo, ssk, p1, ssk, k2tog, ssk, p1'],
  ['generated control 1',
   [[['ssk', 'k', 'k', 'k', 'k', 'k', 'k'], ['k', 'ssk', 'yo', 'k2tog', 'k2tog', 'ssk', 'ssk'],
     ['yo', 'yo', 'p', 'yo', 'p', 'ssk', 'k']],
    1, True, False],
   'k6, ssk'],
  ['generated control 2',
   [[['k2tog', 'p', 'yo', 'yo'], ['k', 'yo', 'k2tog', 'yo'], ['ssk', 'p', 'k2tog', 'k2tog']], 1, False,
    False],
   'yo x2, p1, k2tog'],
  ['generated control 3',
   [[['ssk', 'k2tog', 'ssk', 'k2tog', 'yo'], ['ssk', 'k2tog', 'ssk', 'yo', 'ssk']], 1, False, False],
   'yo, k2tog, ssk, k2tog, ssk']],
 [['in the round', [[['k', 'p'], ['ssk', 'k']], 2, True, False], 'k1, ssk'],
  ['out of range', [[['k']], 3, False, False], 'error: no such row'],
  ['RS row', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'k', 'k']], 1, False, False],
   'k2tog, yo, p1, k2'],
  ['regression: rounds have no WS',
   [[['yo', 'yo', 'k2tog'], ['yo', 'k2tog', 'k2tog'], ['k2tog', 'p', 'k2tog'], ['k', 'ssk', 'yo'],
     ['p', 'ssk', 'k']],
    4, True, False],
   'yo, ssk, k1'],
  ['repair check: rounds have no WS',
   [[['ssk', 'ssk', 'ssk', 'k2tog'], ['p', 'p', 'k2tog', 'ssk']], 1, True, True], 'k2tog, ssk x3'],
  ['generated control 1',
   [[['k', 'ssk', 'k', 'k', 'p', 'k', 'k'], ['k2tog', 'yo', 'yo', 'yo', 'k2tog', 'ssk', 'yo'],
     ['p', 'ssk', 'p', 'ssk', 'k', 'yo', 'k']],
    3, True, False],
   'k1, yo, k1, ssk, p1, ssk, p1'],
  ['generated control 2',
   [[['yo', 'ssk', 'ssk', 'k2tog', 'k2tog'], ['p', 'yo', 'k2tog', 'k2tog', 'p'],
     ['k2tog', 'p', 'k2tog', 'k2tog', 'yo'], ['p', 'p', 'k2tog', 'k2tog', 'p']],
    1, False, False],
   'k2tog x2, ssk x2, yo'],
  ['generated control 3',
   [[['yo', 'yo', 'yo', 'k'], ['ssk', 'ssk', 'k', 'k2tog'], ['ssk', 'p', 'p', 'ssk']], 1, True, False],
   'k1, yo x3']],
 [['out of range', [[['k']], 3, False, False], 'error: no such row'],
  ['RS row', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'k', 'k']], 1, False, False],
   'k2tog, yo, p1, k2'],
  ['WS row swapped', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'ssk', 'k']], 2, False, False],
   'k2, p1, ssp, p1'],
  ['regression: rounds have no WS',
   [[['yo', 'yo', 'k', 'yo', 'yo'], ['yo', 'ssk', 'ssk', 'p', 'k'], ['k', 'k', 'p', 'p', 'yo'],
     ['k', 'ssk', 'p', 'p', 'ssk']],
    1, True, True],
   'yo x2, k1, yo x2'],
  ['repair check: rounds have no WS',
   [[['k2tog', 'yo', 'yo', 'ssk', 'ssk'], ['yo', 'k2tog', 'ssk', 'ssk', 'k'],
     ['k', 'k2tog', 'k2tog', 'k2tog', 'k2tog'], ['k2tog', 'k', 'k', 'k', 'p'],
     ['ssk', 'yo', 'k2tog', 'k', 'yo']],
    1, True, True],
   'ssk x2, yo x2, k2tog'],
  ['generated control 1',
   [[['k', 'p', 'k2tog'], ['ssk', 'k', 'k'], ['p', 'k2tog', 'k2tog'], ['k', 'k', 'k2tog'],
     ['ssk', 'k', 'k2tog'], ['p', 'yo', 'p']],
    1, False, False],
   'k2tog, p1, k1'],
  ['generated control 2',
   [[['k2tog', 'ssk', 'k', 'p', 'yo', 'yo', 'k2tog'], ['k', 'ssk', 'yo', 'k2tog', 'yo', 'p', 'k2tog'],
     ['ssk', 'ssk', 'p', 'k2tog', 'p', 'k', 'yo'], ['ssk', 'yo', 'p', 'k', 'k', 'k', 'p']],
    3, False, False],
   'yo, k1, p1, k2tog, p1, ssk x2'],
  ['generated control 3', [[['ssk', 'k', 'ssk'], ['p', 'k', 'yo']], 2, True, True], 'yo, k1, p1']],
 [['RS row', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'k', 'k']], 1, False, False],
   'k2tog, yo, p1, k2'],
  ['WS row swapped', [[['k', 'k', 'p', 'yo', 'k2tog'], ['p', 'p', 'k', 'ssk', 'k']], 2, False, False],
   'k2, p1, ssp, p1'],
  ['in the round', [[['k', 'p'], ['ssk', 'k']], 2, True, False], 'k1, ssk'],
  ['regression: rounds have no WS',
   [[['yo', 'yo', 'k2tog', 'yo', 'ssk', 'k'], ['k2tog', 'k', 'k2tog', 'p', 'k', 'k2tog']], 2, True, False],
   'k2tog, k1, p1, k2tog, k1, k2tog'],
  ['repair check: rounds have no WS',
   [[['yo', 'yo', 'ssk', 'k'], ['yo', 'k2tog', 'k', 'p'], ['ssk', 'ssk', 'yo', 'yo'],
     ['p', 'k2tog', 'k', 'p']],
    3, True, True],
   'yo x2, ssk x2'],
  ['generated control 1',
   [[['ssk', 'k', 'k'], ['yo', 'k', 'yo'], ['ssk', 'p', 'ssk'], ['k', 'yo', 'yo']], 2, False, False],
   'yo, p1, yo'],
  ['generated control 2',
   [[['k2tog', 'p', 'p', 'k', 'yo', 'k2tog'], ['ssk', 'k2tog', 'p', 'k', 'p', 'yo']], 1, False, False],
   'k2tog, yo, k1, p2, k2tog'],
  ['generated control 3',
   [[['yo', 'k', 'k', 'ssk', 'p', 'yo', 'yo', 'k2tog'], ['yo', 'ssk', 'k2tog', 'ssk', 'yo', 'k', 'yo', 'k'],
     ['yo', 'p', 'p', 'p', 'p', 'k', 'p', 'k'], ['yo', 'p', 'yo', 'ssk', 'k2tog', 'p', 'p', 'ssk'],
     ['p', 'p', 'yo', 'ssk', 'k', 'yo', 'k', 'yo']],
    2, False, False],
   'yo, ssp, p2tog, ssp, yo, p1, yo, p1']]]
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
RS rowk2tog, yo, p1, k2k2tog, yo, p1, k2Passed
WS row swappedk2, p1, ssp, p1k2, p1, ssp, p1Passed
in the roundk1, sskk1, sskPassed
regression: rounds have no WSp1, k1, p1, yo, k2p2, yo, k1, p1, k1Failed
repair check: rounds have no WSp2, yo x2, k1p1, yo x2, k2Failed
generated control 1k2tog, yo, k2tog, yo x2, ssk x2, p1k2tog, yo, k2tog, yo x2, ssk x2, p1Passed
generated control 2ssk x2, k2tog, k1ssk x2, k2tog, k1Passed
generated control 3k2, yo, p1, ssp, p1k2, yo, p1, ssp, p1Passed

SHA-256 / ba1515f0ebacf23e61d4fd0d32d5b8ca57caadf1fa5e92a7097f90648e18678a

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 8 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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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 2026-09-29T14:52:32.518759+00:00.

Case digest / 8e7c269d2c20f74e2019d788a100b317cf5eedb942f3a1c9f108ac073a517fc2