//plugins/captcha_pi.php

if ($word == '')
{
  $pool = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';

  $str = '';
  for ($i = 0; $i < 8; $i++)
  {
    $str .= substr($pool, mt_rand(0, strlen($pool) -1), 1);
  }
		
  $word = $str;
}