There were some surprise winners at the American Crossword Puzzle Tournament last weekend in Brooklyn, even as last year's victor, Dan Feyer, won his second straight championship. Filling in answers to a very difficult puzzle with a dry erase marker on a whiteboard before a crowd of 600 vanquished contestants, Feyer defended his title in rather anticlimactic fashion, beating the runner-up by more than three minutes. (Finishing second was none other than Tyler Hinman, whom viewers of the 2006 documentary Wordplay would recognize as the red-haired wunderkind who became the tournament's youngest champion. Hinman went on to win the next four competitions before being deposed by Feyer).
No, the surprise winner wasn't Feyer, but the 140 entrants—about a quarter of the total—who bested Dr. Fill, a ruthless competitor with a novel approach to solving and with a realistic shot at finishing first, despite having never competed at the tournament before.
Allow me to explain.
Dr. Fill is a computer algorithm created by Matthew Ginsberg, an AI expert and crossword constructor. It's not the first of its kind—a team of computer scientists from Duke brought a cyber-solver called Proverb to the tournament in 1999—but it's undoubtedly the best: While Proverb limped to a bottom-half finish, in simulations of the previous 34 tournaments, Dr. Fill would've won three outright.
The name "Dr. Fill" is a pun on Dr. Phil McGraw, and in crossword lingo, "fill" also refers to the words in the grid (the "entries") collectively. Not coincidentally, fill is one facet of crossword puzzles that computers have already mastered, not in the solving but in the making: While it takes human ingenuity to come up with lively themes and tricky clues, computers have proven adept at generating interlocking words to fill in the white squares.
That's a pretty straightforward task for a machine: Draw from a database of kosher character strings and fit them into a grid. It's a math problem. But finding answers to clues like "Late riser?" (GHOST) or "Turn left, say?" (RADICALIZE)—that's a taller order.