# build the grid
my @grid;
my @row = qw/01 02 03 04 05 06 07 08 09 10 11 12/;
for (1..$NUMBER_OF_ROWS) {
    push @grid, \@row;
}

##</code><code>##

#! perlmy @grid;
use strict;
use Data::Dumper;

use constant NUMBER_OF_ROWS => 12;

my @grid;
my @row = qw/01 02 03 04 05 06 07 08 09 10 11 12/;
for (1..NUMBER_OF_ROWS) {
    push @grid, \@row;
}

print Dumper \@grid;
__END__
$VAR1 = [
          [ '01', '02','03', '04', '05', '06', '07', '08', '09', '10', '11', '12' ],
          $VAR1->[0],
          $VAR1->[0],
          $VAR1->[0],
          $VAR1->[0],
          $VAR1->[0],
          $VAR1->[0],
          $VAR1->[0],
          $VAR1->[0],
          $VAR1->[0],
          $VAR1->[0],
          $VAR1->[0]
        ];

##</code><code>##

my @grid = ( [ '01' .. '12' ] ) x 12;

##</code><code>##

my @grid = ( .... ) x $n;

##</code><code>##

my @grid = map{ ... } 1 .. 12;