This is the 3rd piece that uses a Basic Stamp II microcontroller to program the displays.  Each 4 character display counts up from 0 to a random value up to 2000, sometime later it turns off.  I found that it would take too long to count in a linear way to a high value while also showing interesting movement in the display, so I "faked" the count to jump random increments so that a full count takes less than 5 seconds while looking "busy".

THE DISPLAY TECHNOLOGY

I found these green LED displays in a surplus catalog - there were 4 display chips mounted to a circuit board that might have been designed for a cash register.  Each of the chips is "intelligent" - meaning that a driver circuit performs data decoding and font generation.

Here is what the parts look like when removed from their sockets:

Each unit has a grid of tiny green LED dies on gold pads and embedded in epoxy, they really are pretty!