La torre di Hanoi

In a Tibetan monastery—so an ancient Eastern legend goes—there are three rods fixed into the floor of a room; at the beginning of the world, 64 concentric disks were arranged on the first rod, with the smallest ones resting atop the larger ones. Since the dawn of time, monks have been moving one disk at a time from one rod to another, aiming to transfer the entire stack to a different rod, all while ensuring that a larger disk is never placed upon a smaller one. According to the legend, the world will end when the monks complete their task.

For our purposes, we will limit the height of our towers to a maximum of 8 disks. Our program must be capable of displaying the initial stack of disks and the movement of a single disk from one stack to another on the screen; it must accept and execute our moves—verifying their validity—and signal when we have successfully moved the entire stack, thereby solving the problem.

Published in the book "20 Programmi per Commodore 64"