On a historical note, Nixies were invented for numerical displays prior the advent of so-called "Numitron" tubes (an evacuated tube containing a number of tungsten filaments of the sort found in lightbulb), which themselves were used prior to the common availability of LED 8-segment displays for numerical indication.
Nixies are tubes filled with neon gas with multiple cathodes, each in the shape of a different digit. They're quite detailed and finely made works of art. Although Western production had largely ceased by the 70s, the USSR kept producing them all the way until the fall of the Iron Curtain. Most of the IN-8 tubes (which are used on my clock and on Rich's clock) were produced in the 80s. What's especially interesting is the driver for the Nixie tubes are solid state microelectronics, also produced by the USSR, which leads to an interesting juxtaposition of the 50s-era tubes being controlled by (relatively) modern electronics.
