use Benchmark;
use Symbol;
my $fh = gensym;
open $fh, ">/dev/null" or die;

my($one, $two, $three, $four) = ('a'..'d');

timethese(1_000_000, {
     interp => sub {
         print $fh "$one$two$three$four";
     },
     list => sub {
         print $fh $one, $two, $three, $four;
     },
     conc => sub {
         print $fh $one . $two . $three . $four;
     },
});