Google Turing Machine

Today is apparently Alan Turing’s 100th birthday. To celebrate, the Google logo on their homepage is a Turing-machine! It is even interactive. There are 6 “programs” that you have to change slightly to try to fill in all of the colors in the word Google. I put “programs” in quotation marks because they aren’t written with a delta-function and all that fun stuff, so it took me a while to figure out what the “programs” were supposed to do. Still…every single program in the universe can technically be calculated with a Turing-machine, so they are certainly valid programs.

The thing is…you really have to be a computer science major to ever have heard of a Turing-machine. It is one of those things. And I am currently working a lot with them. They are pretty much the main point of Computer Science 4. Pretty much everything is based on Turing-machines. DFAs, NFAs, and PDAs are all simplified versions of Turing-machines. When proving almost anything dealing with the Chomsky-Hierarchy, you run into a Turing-machine of some sort. And if you can prove that something can be calculated on a Turing-machine, you’ve just proved that it can be calculated.

So I guess I am officially a computer science geek. Because seeing a Turing machine on the Google homepage just made my day.

(The program, in this case, is to move the head left twice. Then, when it hits the yellow button, it overwrites the symbol in the small box with the symbol in the circle right below it and follows the directions. Your job is to change the yellow  button so that the program functions correctly. The goal is to produce the word in the upper right hand corner. The solution here is to change the yellow button so that it overwrites the blank symbol. Then it cycles to the end of the word and is finished)


  1. I tried it but I didn’t suceed. I never heart of the turing machine before. I mean ther is a certain logic behind it (it seems to test whether something is true or false in a certain algorithm)but I didn’t get it 😀 Glad you tried it. Did you succeed writing google?

    • Yeah…I solved all of them. In comparison to have to actually write a Turing-machine it was extremely easy. A Turing-machine is a concept pretty much only known within computer science. It has a band, a head that points to the current position on the band, and a bunch of rules that allow you to determine what the head is supposed to do. It can only rewrite symbols, but with the right rules, you can actually calculate anything.


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