Aug 4, 2014
John Venn's 180th Birthday
http://www.google.com/logos/doodles/...33568.2-hp.jpg
http://www.google.com/doodles/john-venns-180th-birthday [interactive]
John Venn was a logician and philosopher best known for introducing the Venn diagram. In the diagram, circles are used to visually and logically sort groups to illustrate their relationships to each other. For example, one circle may contain things that are mammals. The other circle may contain things that have wings. The overlapping space that both circles occupy would consist of mammals that have wings.