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combinatorics
Multimedia
The Nine Schoolgirls Challenge
Solve this variation of Thomas Kirkman’s famous 1850 puzzle by arranging girls in walking groups. And think fast — the clock is ticking.
Mathematics
A Design Dilemma Solved, Minus Designs
A 150-year-old conundrum about how to group people has been solved, but many puzzles remain.
Mathematics
For Persi Diaconis’ Next Magic Trick …
A mathematician who has analyzed card shuffling for decades is tackling one final nemesis: “smooshing.”
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