Hugh Pickens writes "Steve Lohr reports that an impressive crossword-solving computer program called Dr. Fill matched its digital wits against 600 of the nation's best human crossword-solvers, finishing only 141st at the American Crossword Puzzle Tournament in New York. 'I wish it had done better,' says Dr. Matthew Ginsberg, the creator of Dr. Fill and an expert in artificial intelligence. Dr. Fill typically thrives on conventional crosswords, even ones with arcane clues and answers; it solved one of the most difficult puzzles at the tournament perfectly. But the computer does poorly with clever clues based on puns or jokes, because humans and machines solve the crosswords very differently. Humans recognize patterns based on accumulated knowledge and experience, while computers make endless calculations to determine the most statistically probable answer. The computer program is literal minded, and tends to struggle on puzzles with humor, and puzzles with unusual themes or letter arrangements. Take this clue from a 2010 puzzle in The Times: Apollo 11 and 12 (180 degrees). The answer is SNOISSIWNOOW, seemingly gibberish. A clever human could eventually figure out that those letters, when rotated 180 degrees, spell MOON MISSIONS. Humans get the joke, while a literal-minded computer does not. 'Occasionally, Dr. Fill just doesn't get it,' says Ginsberg. 'That's my nightmare.'"