use strict;
use warnings;
use POE;

my $in    = 0;
my $count = shift || 1000;

POE::Session->create(
   inline_states => {
      _start => sub {
         rand () ** 2 + rand () ** 2 < 1 && $in ++
      },
   },
) for 1 .. $count;

POE::Kernel->run();

printf "Pi equals %f\n", 4 * $in / $count;