The **= sign is called the Exponent AND Assign Operator.
It takes the value on the left, raises it to the power of the value on the right, and saves the result in the same variable.
The value on the right side is being input into the variable on the left side.
Syntax:
$variable **= value;Example:
<?php
$x = 2;
$x **= 3; // raises $x to the power 3, now $x is 8
?>Output:
8