Lightcomb (aka Pushbroom)

A column of lights attached to a rod (ranging in size from a comb with tiny lights on each tine to a broomstick with Christmas tree bulbs) and connected to a microprocesser that causes the lights to flash in programmed patterns. As the rod is swept sideways, these patterns form words or images (as programmed) - an effect similar to that of waving a sparkler around, and best viewed with a long-exposure photograph. For example, to generate an H, the following sequence could be used:
1. All lights on
2. Centre light only
3. Centre light only
4. All lights on

Thus, we'd see:

*  *
*  *

This is easier to show than to explain.