Puzzles
Bulgarian Solitaire
Take 15 tokens and split them into any piles you like — say 10, 3 and 2. Now repeat this move forever: take one token from every pile, and gather all the tokens you removed into one brand-new pile. Piles that hit zero disappear. What eventually happens if you keep going?
Reveal the answer
The piles are guaranteed to settle into the unique stable pattern 1, 2, 3, 4, 5 and stay there forever, no matter how you started. Martin Gardner introduced the game in his Scientific American column in August 1983; the 'Bulgarian' name came from mathematician Henrik Eriksson.
— Martin Gardner, Last Recreations: Hydras, Eggs, and Other Mathematical Mystifications — Originally Scientific American, 'Mathematical Games', August 1983
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