5-Segment Display page 2
Here is the official layout for the segments.
In a clock configuration there would be 4 such digits. The total number of data lines is conveniently 16 - the 10s of hours digit need not be complete. The clock could be driven by a 16-channel relay board or some other display drivers with no strobing.
It may not take 5 data lines. With some gates one segment could be driven by the others as long as the remaining four provide unique patterns.
The 10s digit of hours in a 12-hour clock, segments 'c' and 'd' could be tied together. The display would read either OFF or '1'.
Animated GIF legibility test.