Ronald Dekker made this “mixed signal” LED clock. He writes:
The term “mixed-signal” is usually reserved for circuits and ICs that process both analog and digital signals. In that sense the title “A mixed-signal LED clock” is perhaps misleading since this is a digital clock from beginning to end. However, the readout is analog and since the beast had to be given a name, I a called it my “mixed-signal” clock. A (literally) striking feature about this clock is that it has a real mechanical bell which strikes the hours. It gives the clock quite an homely appearance, and it has became a much valued member of our household.