Google doodle: comemorates 100th anniversary of Alan Turing

(23/June/2012)

https://www.google.com.br/
http://techie-buzz.com/tech-news/google-doodle-celebrates-alan-turing-birthday.html
http://searchengineland.com/solve-the-alan-turing-google-logo-puzzle-125787
http://www.youtube.com/watch?v=84pbZSt_a9k

And a Lego Turing Machine: http://www.wired.com/underwire/2012/06/lego-turing-machine/?utm_source=Contextly&utm_medium=RelatedLinks&utm_campaign=Previous

And a good explanation in the excellent blog Good Math, Bad Math, jun 26, 2012