Consider the following variant of the towers of Hanoi problem. There are 2n discs of increasing size stored on three poles. Initially all of the discs with odd size (1,3,...,2n - 1) are piled on the left pole from top to bottom in increasing order of size; all of the discs with even size (2,4,...,2n) are piled on the right pole. Write a program to provide instructions for moving the odd discs to the right pole and the even discs to the left pole, obeying the same rules as for towers of Hanoi.