Everybody should make his own clock.
flip-flop 7- segment are used to show time.
Relay-based T-triggers would be used to count time. RES-9 is good enough to do this.
"One primary clock - many Secondary clock" system
Secondary HH:MM clock have STOBE input and each minute receive impulse from a "Primary" clock(in the middle of the picture). This system was widely used to cover huge region with precise time - all secondary clocks (on the left and on the right on the picture) ever shows the same time because all of them connected to one primary clock source.
Each digit have 7 magnets. For opening segment we need to connect magnet to DC for a short time. If we want to switch segment - We need to change polarity and send impuls again.
My first idea is to use Diode selector and relays for selecting segments. Two relays should change polarity for appropriate segments