# example: build a 10x10 boolean field on a hash key
 my $key='10x10';   
 my %hash;

 for my $row (0..9) {
    for my $col (0..9) {
       push @{  
              $hash{$key}[$row] 
             }, 
             int(rand()+0.5);
    }
 }

##</code><code>##

 for my $row (0..9) {
    for my $col (0..9) {
       print "{$key} => [$row][$col] = $hash{$key}[$row][$col] \n"
    }
 }