my @a = ( 3, 1, 4, 1, 5 );
my $N = @a;
say $N; # or print "$N\n; before 5.10
my $aref = \@a;
$refsize = @$aref; # or @{$aref};
say $refsize;

##</code><code>##

my @twoD = ( [ 1, 2, 3 ],
             [ 4, 5, 6 ],
           );
print "Top level or array has " . scalar @twoD . " elements\n";
for my $row ( @twoD ) {
   print "row has " . scalar @$row . " elements\n";
}