This weekend I managed to complete the single-minutes stage of the clock. After testing the flip-flop's and building the decoder I could finally connect everything together. The completed seven segment display has been sitting on my bench for months, waiting to be used. I now have one working digit. This is a milestone for me, the first time I have everything working from the counting logic to the display. As you can see in the video, the clock signal is generated externally by an Arduino. For now anyway. Enjoy the soothing clicking of the relays.