This program I have wrote in Processing is designed to simulate the input and output from an Arduino Board circuit.
In a module at University (Sound and Light) we hook up this board to a computer and use various wires, buttons, potentiometers and LEDs, etc.
On the computer we write programming code to decide what to do with the various inputs and outputs, such as two buttons turning two LEDs on, but if both are pressed nothing happens.
To the program, the point in it, is that I found that the circuits sometimes it was hard to get something to work, or you didn't do something right, but I wanted to write code in a way I wouldn't have to worry about connections until I made the circuit itself
So I made this little program to do just that, I can write the code and see instant output in real time.
If requested I can make the program available for others to use, it doesn't implement every feature of Arduino but does include several