All I have to say about this visualizing savant is: WOW
Bret Victor is a former user interface (UI) designer for Apple. His website and his work are a total inspiration. The area of his work primarily focuses now on data visualization for the betterment of society (America as well). In an interview with FastCo Design, Bret explains that he left Apple because he has "zero interest in helping people look through photos and listen to music". I couldn't agree more.
I'm glad that he has taken his skills to arenas beyond Apple production. We can all thank him for the work he did on the iPad and iPhone (thank you!). But as far as I can tell, projects like 'Kill Math' and his in-depth paper on the graphical interface 'Magic Ink' are worth his resignation. I can't wait to see what other dynamics he produces in the coming years...
I truly recommend taking a look through his entire website. (Warning: You will undoubtedly spend a lot of time there and become addicted to his method, process, theory, foresight, genius, madness, etc...)