Euler's Bridges

Lenhard Euler was a Swiss mathematician of the 18th century, born 304 years ago today. By studying graph theory, he solved the problem of the seven bridges of Konigsberg, Prussia. This town had two islands in the middle of the river connected by 7 bridges. The challenge was to cross all bridges exactly once and return to the starting point.
See Also: http://en.wikipedia.org/wiki/Seven_Bridges_of_K%C3%B6nigsberg

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