“Illinois is green, Indiana is pink. You show me any pinkdown there, if you can. No sir, its green . . .”“Huck Finn, did you reckon the States was the samecolor out of doors as on the map?”“Tom Sawyer, what’s a map for? Ain’t it to learn youthe facts?”“Of course.”“Well, then, how’s it going to do that if it tells us lies?That’s what I want to know.”—Mark Twain, Tom Sawyer Abroad1

The mathematician Charles Lutwidge Dodgson (1832–1898), better known as Lewis Caroll, author of Alice in Wonderland, invented the following two-person game. Person A draws a map of a continent with any number of countries. Then person B colors the map so that neighboring countries (they have to share a border, touching at a corner does ...

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