#!/usr/bin/perl -w

use Tk;
use strict;    

my $mw = MainWindow->new;
my $c = $mw->Canvas(
-width => 500, 
-height => 500, 
-background =>'blue', 
-scrollregion =>[0, 0, 100, 100]); 
$c->pack; 

$c->createRectangle(100, 100, 150, 150, -fill => 'yellow'); 

MainLoop;