After the first deref, deref is assumed. Given:

  my $aref = [1,2,[3,4,5,[6,7] ] ];

You can do

  print $aref->[2][3][1];

which yields:

  7

Or

  my @array = (1,2,[3,4,5,[6,7] ] );
  print $array[2][3][1];
  7