We are confusing here two slightly different
, yet related
puzzles. The first is "given word string s, parse it correctly
" (the "had had" puzzles) while the second is the seemingly harder "generate a word string conforming to an unusual constraint that satisfies the rules of grammar
" (the "and and" puzzles).
Obviously, TenMinJoe provides an excellent (IMHO) 'solution', that is perfectly valid. However, it would be marked wrong in an exam - why? Presumably, because it follows the letter and not the spirit of the test. However, even the first ("had had") puzzles have potential solutions that could be considered 'invalid'. Consider:
John, while Mary had had "had," had had "had had." "Had had" was correct.
To save you straining your eyes, this is simply a symmetry reversal*
of the situation. Possibly a politically incorrect
one, since it is now Mary who is wrong! :) In any case, it is clear that there are several
possible solutions - there is no unambiguous
way of parsing the sentence. Just as with those annoying "series completion" tests you get in IQ test
s, a purely mechanical approach to determining the 'correct' answer is doomed to faliure.
*I'm currently distracting myself from combinatorial graph generation, which is why this looked obvious to me! :)