if (count($bits)==1) {
                if (preg_match('/bottom/',$bits[0])) { $bg['p'] = '50% 100%'; }
                else if (preg_match('/top/',$bits[0])) { $bg['p'] = '50% 0%'; }
                else { $bg['p'] = $bits[0] . ' 50%'; }
            }