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

my ($s1,$s2,$s3,$s4) =(0,0,0,0);
my @slider;
my $i;

sub show_vals {
print "SLIDERVALUES = $s1 $s2 $s3 $s4\n";
}

# window setup 
my $mw = MainWindow->new;

$slider[1] =$mw->Scale(
    -from    => 30,
      -to    => 0,
      -orient    => 'vertical',
      -variable    => \$s1,
     )->pack(-side    => 'left');

$slider[2] = $mw->Scale(
      -from    => 30,
      -to    => 0,
      -orient    => 'vertical',
      -variable    => \$s2,
     )->pack(-side    => 'left');

$slider[3] = $mw->Scale(
      -from    => 30,
      -to    => 0,
      -orient    => 'vertical',
      -variable    => \$s3,
     )->pack(-side    => 'left');

$slider[4] = $mw->Scale(
      -from    => 30,
      -to    => 0,
      -orient    => 'vertical',
      -variable    => \$s4,
     )->pack(-side    => 'left');


show_vals();

($s1,$s2,$s3,$s4) = (5, 10, 15, 20);
show_vals();
($s1,$s2,$s3,$s4) = (7, 14, 21, 28);
show_vals();

$mw->update;
MainLoop;