Exponentiation

<?php
printf("2 ** 3 ==  %d\n", 2 ** 3);
printf("2 ** 3 ** 2 == %d\n", 2 ** 3 ** 2);

$a = 2;
$a **= 3;
printf("a == %d\n", $a);
?>

<?php
printf("2 ** 3 ==  %d\n", 2 ** 3);
printf("2 ** 3 ** 2 == %d\n", 2 ** 3 ** 2);

$a = 2;
$a **= 3;
printf("a == %d\n", $a);
?>

2 ** 3 ==      8
2 ** 3 ** 2 == 512
a ==           8