function getCount()
{
    static $count = 0;
    $count ++;
    return $count;
}

for ($i = 0; $i < 10; $i ++) {
   echo getCount(), "\n";
}
/* output:
1
2
3
4
5
6
7
8
9
10
*/

function fibV2($n)
{
    static $result = array();
    if (!isset($result[$n])) {
        if ($n <= 2) {
            $result[$n] = 1;
        } else {
            $result[$n] = fibV2($n - 2) + fibV2($n - 1);
        }
    }
    return $result[$n];
}