#!/usr/bin/perl
use warnings;
use strict;
use Tk;

my $mw = MainWindow->new();

# first create a canvas widget
my $canvas = $mw->Canvas(width => 300, height => 200)->pack();
my $one = $canvas->createOval(5,  0, 20, 30, -fill => 'blue');
my $two = $canvas->createRectangle(0, 20, 50, 75, -fill => 'red');
my $three = $canvas->createRectangle(40, 80, 100, 175, -fill => 'green
+');


my $group_ref = [$one, $two];
my $group = $canvas->createGroup([0, 0], -members => $group_ref);

my $dx = 1;
my $dy = 1;
my $id = Tk::After->new($canvas,10,'repeat', 
             sub {$canvas->move($group, $dx,$dy); 
                 my ($x,$y) = $canvas->bbox($group);
                 print "$x $y\n";
                 if($y >= 100){$dy = -1};
                 if($x >= 200){$dy = 1; $dx = -1}; 
                 if($x < -5){$dx=1;$dy=1};
          });


my $gbutton = $mw->Button(-text => 'Change Group',
                  -command => sub{
                  push @$group_ref, $three;                  
                  $canvas->itemconfigure($group,-members=> $group_ref)
+;
                  })->pack();


my $sbutton = $mw->Button(-text => 'Stop',
                  -command => sub{$id->cancel;})->pack();


my $ebutton = $mw->Button(-text => 'Exit',
                  -command => 'Tk::exit')->pack();

                  
MainLoop();
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