Graphpaper is, in short, a notecard simulator, with the additional
feature that you can show relationships between cards with arrows.
The default file has more detailed instructions for using the
program.

Installation:

Graphpaper needs Python with the Tcl/Tk bindings. There are no other
external dependencies. There are instructions for installing Tk here,
if you don't already have it after installing Python:

  http://www.tkdocs.com/tutorial/install.html

On Windows, you simply need to install Python from python.org. The
installer includes Tcl/Tk by default. Then you just need to extract
the zip archive of graphpaper (or the Git repository) somewhere
convenient and double-click on graphpaper.py.

On a Mac, you probably already have Python, and may already have Tk,
but I don't know for sure. If not, try following the directions above.

On Linux, install Python and Tk in whatever manner is appropriate for
your distro. On Ubuntu, I believe you would use the command:

  sudo apt-get install python tk8.5 python-tk