Hanoi Towers puzzle simulator

This digital circuit implemented with TTLs (74XX) was designed and constructed as an individual semester project for the "Digital systems Lab" course of the 6th semester. In this project the student had the freedom to implement something self-inspired as long as it was complicated enough. Actually it didn't need to be so complicated but I did it just for fun...! Hopefully it worked !!! It can identify all kinds of invalid movements of the discs and warns the user (the small green led that is ON goes OFF whereas the red one next to it goes ON) before he validates his answer by pressing the top right button. The bottom button under each column is used in order to specify that you want to take a disc from that column whereas the top one to specify that you want to place a disc there. If you want to start over you press the button on the bottom left corner in order to reset the circuit. It is powered by a SONY adapter that was once used to charge my old mobile phone...

The front view...

The back view...