for (@words) {
    print if /foo/;
  }

##</code><code>##

  my $s = "foo";
  for (@words) {
    print if /$s/;
  }

##</code><code>##

  my($s1, $s2) = qw/ foo bar /;
  for (@words) {
    print if /$s1/;
    print if /$s2/;
  }

##</code><code>##

  my @s = qw/ foo bar /;
  for (@words) {
    for my $s (@s) {
      print if /$s/;
    }
  }

##</code><code>##

  my @s = map qr{$_}, qw/ foo bar /;
  for (@words) {
    for my $s (@s) {
      print if /$s/;
    }
  }