#!/usr/bin/perl -w
use strict;

my @mainarr;
my @arr1=qw(a b c d e);
my @arr2=qw(f g h i j);
my @arr3=qw(k l m n o);
push(@mainarr,@arr1);
push(@mainarr,@arr2);
push(@mainarr,@arr3);

# you have flattened each list into a single list
# The "push" is similar to a queue operation
# that adds things to the end of the queue.
# there are 4 Perl ops that you should read more
# about (push,pop,shift,unshift), all of these operate
# on lists. 

print "@mainarr\n"; 
# that prints: a b c d e f g h i j k l m n o

print join(" ",@mainarr[5..9]),"\n";
# this is a list slice and prints the 6th-10th things...
# this prints: f g h i j

#If you want to maintain the integrity of these things
#that you "push" onto @mainarr, then they have to be
#grouped together. The way to do that is with a 
#reference to a list. This creates a LoL, a List of List.

push(@mainarr,[@arr1]);
push(@mainarr,[@arr2]);
push(@mainarr,[@arr3]);

print "@mainarr\n"; 
#will produce something like:
#ARRAY(0x182a64c) ARRAY(0x183642c) ARRAY(0x183649c)

foreach $list_ref (@mainarr)
{
   print "@$list_ref\n";
}

#this prints:
#a b c d e
#f g h i j
#k l m n o