Here's a quickie that does what you ask, based on an array of arrays.

#!/usr/local/bin/perl -w
use strict;
my @segment;
$segment[0]=[ qw(one two three four) ];
$segment[1]=[ qw(red blue green yellow) ];
$segment[2]=[ qw(a b c d) ];
print "Pairs for segment ".($_+1)." are: \n", join "\n", get_pairs($se
+gment[$_]), "\n" for (0..2);
sub get_pairs {
  my $aryref=shift;
  my @pairs;
  push @pairs, $aryref->[$_-1].$aryref->[$_] for (1 .. $#$aryref );
  return @pairs;
}
__END__
Pairs for segment 1 are: 
onetwo
twothree
threefour

Pairs for segment 2 are: 
redblue
bluegreen
greenyellow

Pairs for segment 3 are: 
ab
bc
cd
[download]

I strongly suggest that you read some documentation. Learning Perl is a good place to start.

CU
Robartes-