DB<1>  @c = (1,2,3,4);

  DB<2>  for ($i = $#c; $i>=0;$i--) {push @d,  $c[$i]};

  DB<3> x @d
0  4
1  3
2  2
3  1
  DB<4> unshift @e,  $_ for @c;

  DB<5> x @e
0  4
1  3
2  2
3  1