neon lamps are used in many military applications as indicators, voltage regulators, relaxation oscillators (i.e. generating sawtooth waves for oscilloscope or radar displays). due to the shape of the elements, this is likely some kind of indicator. voltage regulator elements are usually a rod or small diameter cylinder for the cathode, surrounded by a larger cylinder for the anode. discharge tubes and indicators can have any convenient element shapes, although discharge tubes would likely be parallel identical plates. for indicators, the elements can be any shape that meets the need, NE2 lamps are just two parallel rods, nixie tubes have elements in the shape of digits, decorative lamps have elements in the shape of a candle flame, and are operated at a current where the discharge is unstable (which makes it flicker like a candle).