FlipDots are like LEDs form another time and the best part of it: they can even display information without any current.
FlipDots are driven by a coil wound around a metal core, that can hold its magnetisation. The dots are simple plastic plates but with a magnet inside. The principle is like bistable relays, once you’ve driven the coil, the dot flips in the corresponding direction and stays there until you apply reverse current.
Note the different variants: the Brose variant has a straight outline, while the InfoSystems are curved (better vertical alignment).