Happy Birthday, John Venn, Inventor of the Venn Diagram.

You probably see Venn diagrams all over the place, and didn't realize that they're named after John Venn, the British mathematician born on August 4, 1834 (183 years ago for those who don't like math).

John Venn didn't name the diagram after himself. The Venn diagram was named such by American philosopher and pragmatist Clarence Irving Lewis in his 1918 book “A Survey of Symbolic Logic.”

Mark Perry, an economics and finance professor at University of Michigan-Flint and author of the Carpe Diem blog, is an AVID fan of Venn diagrams. He uses them regularly, and in many entertaining ways. His "intellectual consistency" diagrams are a running gag so he put together a few to celebrate Venn's birthday. Here are some fun (ok, also nerdy and possibly vexing) ones!

On protectionism.

On carbon footprints.

On the "wage gap."