#!/usr/local/bin/perl -w
use Tk;
use strict;
require Tk::Label;
my $fred = 'Something';
sub toggle
{
use vars qw($callback);
my $w = shift;
my $r = $w->configure("-relief");
$w->configure("-relief" => ($r eq "raised") ? "sunken" : "raised");
$fred = reverse($fred);
$callback = [\&toggle,$w] unless defined $callback;
$w->after(1000,$callback);
}
my $top = MainWindow->new();
my $l = $top->Label('-textvariable'=> \$fred);
$l->pack();
&toggle($l);
$top->update();
Tk::MainLoop();