The blank screen reminds you that the mouse-based graphical user interface (GUI) that allows you to point-and-click to get things done on a computer is not how things have always got done:

http://www.flickr.com/photos/johnseb/6448275739/

[my first computer was a BBC B microcomputer]

and also that the invention of the mouse was a pretty miraculous advance:

http://sloan.stanford.edu/mousesite/1968Demo.html

though not an unalloyed blessing to all:

http://pauillac.inria.fr/~weis/info/commandline.html

[Neal Stephenson’s famous essay

http://www.amazon.co.uk/Beginning-Was-Command-Line-Neal-Stephenson/dp/0380815931

— something like a cry from the heart about freedom and the ways in which we use or allowed to use computers]