Google's latest Doodle marks the 180th anniversary of the birth of English philosopher John Venn, inventor of the Venn diagram.

The diagram typically uses two or three circles that represent sets of things that are logically grouped; say 'transport' and 'has wings'. Where the circles overlap all types of winged transport can be found.

This idea is illustrated in a highly interactive Doodle that begins with the search engine's logo made up of coloured cirles. Clicking on this, you can then create your own Venn diagrams using groups such as 'sea life' or 'mammals' overlapped with 'birds' or 'has a shell'.

A cartoon of Venn himself then appears to show the user an example of things that would conform to each possible overlap.


Venn's work, which he referred to as 'Eulerian Circles', is used in set theory, probability, logic, statistics and computer science.