use Tk;
my $mw = new MainWindow;

my $txt = $mw -> Scrolled('Text', -width => 40, 
                                  -height => 10, 
                                  -scrollbars => "oe")->pack();

$txt -> insert('end',
"The primary purpose of the Data statement is to give names 
to constants; instead of referring to PI as 3.141592653589793
at every appearance, the variable Pi can be given that value
with a Data statement and used instead of the longer form of
the constant. This also simplifies modifying the program,
should the value of PI change.

Fortran manual for Xerox Computers");

MainLoop;