Sliding-Coin Puzzles

By Ivars Peterson, 15:49 PM April 15, 2008

Geometric arrangements of coins can serve as the basis for all sorts of puzzles. One popular variant involves going from one configuration to another by sliding coins, subject to given constraints, and doing so in the fewest possible moves.

One classic puzzle, for example, starts with six coins packed tightly together in a rhomboid formation, made up of two nestled rows of three coins each. The goal is to form a ring of coins so that, if a seventh coin were placed in the center, the original ...

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