I came across this graphic in an article on genetic research in population distribution in Iceland for some research I am doing be in (of all things) transportation. If you are a fan of Edward Tufte, this is for you:

The colors on the top left show the genes of the original settlers in the counties of Iceland. The color wheels in the subsequent maps show the mixing of genes as the population moves around and inter-breeds. No text necessary, just an elegant way to show a complex idea.