#!/usr/bin/perl
use Tk;
use strict;
my $text = 'Hello World !!    ';
my $mw = tkinit;
$mw->geometry('+200+200');
$mw->overrideredirect(1);

my $label = $mw->Label(
    -textvariable=>\$text,
    -font=>'courier',
    -bg=>'green',
    -bd=>4,
    -relief=>'ridge'
     )->pack(-fill=>'both');

$label->bind('<ButtonRelease>',sub{$mw->destroy});

# a simple regex that is hard to explain :-)  # a clever trick
$mw->repeat(60,[sub{$text=~s/(.)(.*)/$2$1/;}]);

MainLoop;