Google is celebrating the 100th anniversary of the birth of mathematician Alan Turing with an interactive doodle based on the Turing machine. To complete the doodle, you must modify the string of commands to make your code match the example given. It starts off simply, but gets progressively harder (the image above is the final problem you'll face). It's a lot of fun and our only complaint is that it doesn't last long enough.

Turing is perhaps most famous for his work on the Bombe decryption machine used to crack the German Enigma code during the Second World War and is also cited as one of the fathers of computational science. His work on algorithms, in particular, led the way for modern programming.