This app is a graphical simulator of Turing machines, developed by OTSL Inc. and the School of Informatics and Sciences, Nagoya University.
The concept of Turing machines is one of the most important for studying computability theory. Students of computer science and mathematical logic should be familiar with it. With this app, you can freely draw state diagrams on a canvas, and can execute it with animations. You will see how your machine works by watching the dynamic animations showing the transitions between states.
You can draw programs for Turing machines by touch interface, and add comments to nodes, arcs(transitions), and canvases using the software keyboard. In this app, you can even use "sub-machines." These are very convenient for constructing a complex machine. You can reuse your machine as a sub-machine (a component) of another machine. You can also copy and paste sub-machines between canvases.
Importing / exporting is enabled via email. You can send your machine within the app via email. When you receive an email containing a machine as an attached file, you just tap the attached machine, then the app will automatically import it.
A demo movie: http://youtu.be/M-7ySJuIUpw