Yesterday's Google Doodle which sported a circle revolving around axes, geometrical diagrams and mathematical equations has been put up in honour of Leonhard Euler, who has been described as a "a pioneering Swiss mathematician and physicist".
According to the entry on Wikipedia, Euler made "important discoveries in fields as diverse as infinitesimal calculus and graph theory. He also introduced much of the modern mathematical terminology and notation, particularly for mathematical analysis, such as the notion of a mathematical function. He is also renowned for his work in mechanics, fluid dynamics, optics, and astronomy."
In other words, he was a Godfather of sorts, for the modern day geek - who as we all know, is running the world right now.
Google has special affinity for historical geeks - choosing in the past to honour people like French physicist Louis Daguerre, who created the world's first commercially successful way of capturing permanent photographs and Nasīr al-Dīn Tūsī, who was a Persian polymath and prolific writer: an architect, astronomer, biologist, chemist, mathematician, philosopher, physician, physicist, scientist, theologian and Marja Taqleed.
Euler is widely acknowledged to be one of the greatest mathematicians to have ever lived, working in almost all areas of mathematics: geometry, infinitesimal calculus, trigonometry, algebra, and number theory, as well as continuum physics, lunar theory and other areas of physics.
Most notably according to William Dunham in his book titled Euler: the master of us all, he introduced the concept of a function and was the first to write f(x) to denote the function f applied to the argument x.