Serendip: The Four Color Problem

A famous proof in geometry concerns the four-color problem, which says that only four colors are needed to color a map on which no two countries that have adjacent borders are the same color. It took over a century to prove this theory. You can play with this concept on the site by creating your own “map” and coloring in the spaces using just four colors. Instructions are given on how to generate a map and how to choose the colors for the map segments.

courtesy of Knovation