Tower of Hanoi with PHP

The Tower of Hanoi (a.k.a Tower of Brahma and Lucas' Tower) is a mathematical game or puzzle.

The objective of the puzzle is to move the entire stack to another rod, obeying the following simple rules:
            1. Move only one disk at a time.
            2. A larger disk may not be placed ontop of a smaller disk.
            3. All disks, except the one being moved, must be on a peg.