The neon displays are a late night horror show I made last year. They use the 3 D printed frames and neon displays to produce the big ole digits on this machine:
here are the basic ingredients. These include the inlay frame, the back frame and NE-2 neon bulbs.
Stuffing the frame with ne-2 bulbs.
This is the assembly step: The ne-2 leads are brought through the frame and soldered to dropping resistors.
Here are the finished digits and symbols. Talk about long distance readability!