perl -Mstrict -WE '
my @x = (1,2);
my @y = (3,4); 
for my $z ( @x, @y ) {
    say $z;
}        
'

##</code><code>##

1
2
3
4

##</code><code>##

perl -Mstrict -WE '
my @x = (1,2);
my @y = (3,4); 
for my $z ( @x ) {
    say $z;
}
for my $z ( @y ) {
    say $z;
}
'

##</code><code>##

1
2
3
4

##</code><code>##

perl -Mstrict -WE '
my @x = (1,2);
my @y = (3,4); 
for my $z ( @x ) {
    say $z;
    for my $z ( @y ) {
        say "  $z";
    }
    say $z;
}
'

##</code><code>##

1
  3
  4
1
2
  3
  4
2