This, when cut from paper, will wrap around the outside of my matrix lantern design. I recommend making one out of black paper for an inner layer to keep the light from washing through and an outer layer of what ever color paper you like. I used black card stock for the inside and red poster board for the outside.
This has the same clock face in two locations. This design makes the time visible from a wide viewing angle. Thus, I used a pair of the cheap 8 x 8 matrix panels and tweaked the arduino code to drive 128 LED vs 64 (i.e. 2nd clock). The panels daisy chain together so that made wiring it up easy. I left a blank column between the led panels ( centered over one leg) . That seems like good spacing. It looked a bit odd when they were butted up against each other.
Added note: there is also a layer of white printer paper under the lettered layers to act as a diffuser.