This clock is seperated into 4 pieces which connect by dovetail joints, this allows it to be printable even if your print bed is very small.

On the back is a hole which fits the head of a Nail, for mounting with very little damage to your wall. However, you can also mount it with 3m tape or some other adhesive.

Heres the link to the clock i bought but you can obviously use any one you want - $11 Clock Link