On John Venn's 180th birthday, Google has created an interactive Doodle to remember him and one of his most influential contributions to the world, the Venn Diagram.
The Doodle let's you take two items and overlay them, in the typical Venn Diagram approach.
John Venn was an English logician and philosopher, his Venn Diagram was a way to show all possible logical relations between a finite collection of sets.
Here is a video of the Google Doodle in action:
Here is the static version:
John Venn passed at the age of 88 on April 4, 1923.
The Google Doodlers said:
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.