Is there a limitation on "setWatch"?

Flip dot display:

• Alfazeta FlipDot 7x7 dots display
  
• ShiftOut question for Hannio flipDot Display
  
  

And there are flip dot displays available that have in addition to each flip dot also an LED that is on if the flip dot is 'on': https://hackaday.io/project/159415/logs?sort=oldest

The split flap display is like this: https://www.youtube.com/watch?v=lW0fk_sIdic

• and a nice split flap display you find at: https://www.tindie.com/products/scottbez1/split-flap-display-kit-4-characters/
  
  

Instead of split flaps, you can also use rotating disks... probably the simplest to implement with a few steppers...

Attached is split flap tech drawing / cross cut as found on wikipedia

1 Attachment