use strict;
use Data::Dumper;

my @array;

for (my $i=0;$i<2;$i++)
{
  for (my $j=0;$j<2;$j++)
  {
     @array[$i, $j] = "$i.$j";
  }
}
print "Case 1...\n";
print Dumper(@array);

for (my $i=0;$i<2;$i++)
{
  for (my $j=0;$j<2;$j++)
  {
     $array[$i][$j] = "$i . $j";
  }
}
print "Case 2...\n";
print Dumper(@array);

for (my $i=0;$i<2;$i++)
{
  for (my $j=0;$j<2;$j++)
  {
     $array[$i, $j] = "$i . $j";
  }
}
print "Case 3...\n";
print Dumper(@array);

##</code><code>##

Case 1...
$VAR1 = undef;
$VAR2 = undef;
Case 2...
$VAR1 = [
          '0 . 0',
          '0 . 1'
        ];
$VAR2 = [
          '1 . 0',
          '1 . 1'
        ];
Case 3...
$VAR1 = '1 . 0';
$VAR2 = '1 . 1';