An interesting project. I did see one error in his description of how a register works. What he describes is the operation of a latch. A register does not chang

An interesting project. I did see one error in his description of how a register works. What he describes is the operation of a latch. A register does not change outputs when the clock goes low. It only changes on the rising edge of the clock. See the datasheets for 74373 vs 74374 to see the difference.