Euler diagram to explain the difference between England, Great Britain, the United Kingdom and the British Isles.
Euler diagram - Wikipedia, the free encyclopedia
File:British Isles Euler diagram 15.svg
Venn diagrams morphing into Euler circles.
Euler Diagrams Overview
This is a Euler Diagram of the present state of American politics. Please note: Mitt Romney seems to be "all over the map" here.
Euler and Venn Diagrams: They Aren’t Just for Fun
Euler Diagrams http://plato.stanford.edu/entries/diagrams/fig1.png