Crosswords can be mathematically unique
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As you complete a crossword puzzle, it can suddenly go from incredibly difficult to very simple. This is similar to the way some physical systems undergo a phase transition, but compared to them, these puzzles may be mathematically unique.
While solving a crossword puzzle one day, Alexander Hartmann At the University of Oldenburg in Germany, he created a personal challenge: he wanted to find enough words to create a large, connected island of letters. He then realized that he had inadvertently run into a type of “percolation problem” that was well known…
