Remember my article on The Busy Beaver Problem? Well, someone built a real Turing Machine and decided to run the busy beaver with 4 states on it. Here is the video.

Video URL: http://www.youtube.com/watch?v=2PjU6DJyBpw

The Turing Machine in this video runs for 107 steps and halts with the total of 13 ones, as expected.

In my article on The Busy Beaver Problem, I also wrote a program that visualizes the tape changes. If you follow the video closely, you'll see that they match the visualization (black square stands for 1, white for 0).

Tape changes for 4 state busy beaver.

See A Turing Machine website for more videos and information about how this machine was actually built. Also see my article on Busy Beaver for a Turing Machine implementation in Python and C++.