This is an educational clock to teach the analogue clock. 
Also interesting for lovers of clockworks or gearboxes ;)

Completely printed without supports, no need for glue or screws either!
Also fits onto the Prusa mini (:
 

The hour- and minute hands are connected with a two-staged planetary geared clockwork on the back of the clock. Therefore they move in the correct ratio of 1:12. For a full turn of the minute hand, the hour hand will move one hour.
This can be done by directly moving the minute hand with a finger, or for a better view onto the clock face, by turning the grip on the backside of the clock.

Print specifications of the example in the pictures:

PLA, 0.2mm layer height
2 perimeters, 20% infill
about 20 hours total print time (normal print mode, with same colour separation as in the pictures, could be faster or slower with more or less filament colours)

Assembly:

• Print all parts
  Amount of needed parts is in the notes of the files.
   
• Step 1: 
  slide the connection pins through the holes of the clock_body and attach the clock_face.
  make sure the “12” points towards the upward pin. Then slide the hour and minute hand through the middle hole and make sure both hands point towards “12”.

• Step 2:
  Place the partly assembled clock with the clock face onto the desk. Make sure that both hands still point towards “12”. Then attach the A_planet_carrier onto the hour_hand.
  There is a little triangle engraved into the A_planet_carrier. All triangles of all parts must be installed pointing upwards toward “12”

• Step 3:
  Install the A_gear_ring and the A_sun_gear, both with the triangle pointing upwards. After that install A_planet_gears.

• Step 4:
  Install the B_gear_gring and B_planet_carrier with the triangle pointing upwards.

• Step 5
  Place the B_sun_gear with the triangle pointing upwards. Then place the B_planet_gears.

• Step 6
  Slide the stand_back over the connection_pins and fix it with the small clips.

• Step 7
  Install the grip and fix it with the big clip. Then attatch the stand_bottom

• Finished- have fun!