Alan Turing was born 100 years ago on June 23, 1912. Google celebrates "the father of computer science and artificial intelligence" with an interactive "intelligence test doodle". It's a kind of "Turing machine". The Alan Turing doodle that Google posted on the occasion of British mathematician and the father of computing's 100th birth anniversary is easily the most cryptic Google doodle till date.

Google has brought to digital life one of Turing's incredible work (and an eventful life that ended in tragedy), the theoretical Turing machine that he proposed in a mathematical paper. This Turing machine doodle, unlike most other doodles isn't meant for general Google users but is instead targeted towards those with a knowledge of computer programming - a science of which Turin was a pioneer.

While the initial task on hand seems to be spelling out the letters g-o-o-g-l-e in binary in six steps. On successfully completing each step the letters of the greyed-out Google logo get filled with colour, one at a time. But Google wouldn't have let its tribute to the famous code breaker get decoded in a breeze. "If you get it the first time, try again... it gets harder!," Google said in a post on its official blog. I have to think some minutes before I checked how it works. Here are the results of the 6 tasks. When you did it correct one more Google logo char is filled with color.