A good visual tool for teaching how to solve a classic programming problem. Segues nicely into material for dissecting the problem, developing a solution algorithm and then writing the resulting function.
Discussing the mathematical formula for determining the minimum number of moves needed to solve the puzzle with any number of disks, makes this a good example of what programmers need to consider in order to develop efficiently running programs.
Sometimes the applet controls were only partly visible after loading. This is easily resolved by refreshing the display.