Example 2.4.1 The Tower of Hanoi Problem: Suppose there are $n$ disks stacked on column $A$ in ascending order of size, with the largest at the bottom and the smallest at the top, as shown in Figure 2-7. Now, we need to move all the disks from column $A$ to column $C$, with the constraint that only one disk can be moved at a time and a larger disk cannot be placed on top of a smaller one. Assuming there are three columns $A, B, C$ available for use, how many moves are required to transfer all $n$ disks from column $A$ to column $C$?