>>> a = [0] * 10
>>> a
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

##</code><code>##

>>> a = [1,2]
>>> b = [a] * 5
>>> a
[[1, 2], [1, 2], [1, 2], [1, 2], [1, 2]]
>>> a[0] = 2
>>> b
[[2, 2], [2, 2], [2, 2], [2, 2], [2, 2]]

##</code><code>##

my @a = (1, 2);
my @b = (\@a) x 5;
$a[0] = 2;
print Dumper \@b;