my @a = [ 1, 4, 9, 16];  # squares
my @b = [ 1, 8, 27, 64]; # cubes
my @c = [ \@a, \@b ];    # two arrays

my $d = \@a;
my $e = \@c;

# OK: @a is an array
print "Sample1: ", $a[0]->[0], "\n";

# Wrong: "Sample1: ", $d is a reference, not an array!
#print "Sample2: ", $d[0], "\n";

# OK: Both of these are fine, though
print "Sample3: ", $d->[0]->[0], "\n";
print "Sample4: ", $$d[0]->[0],  "\n";

# with multiple subscripts:
print "Sample5: ", $e->[0]->[0]->[0]->[0], "\n";
print "Sample6: ", $e->[0][0][0][0],       "\n";  # same as above, since -> is optional between subscripts
print "Sample7: ", $$e[0][0][0][0],        "\n";  # also same as above