Believe it or not, coloring is a profound mathematical topic
with many multi-million-dollar industrial applications. The
problem presented here has been of interest to mathematicians for
over a hundred years. Some versions of the problem are easy to
solve, others have yielded only recently to relentless efforts
that would not have been possible without the aid of powerful
computers. In all of its aspects, the basic problem is the
same: How many colors do you need?

With a few crayons or markers and some hand-drawn maps, children
can quickly find themselves grappling with some of the same
conundrums that contemporary mathematicians do.