A flip-disc display is a special kind of screen that shows pictures or words using tiny little discs that can flip over to show different colors. Imagine a big board with lots of little squares, each one containing a tiny disc that can be flipped over like a coin. These discs are made of two different colors on each side, and when they flip over, they show the other color.
When a picture or words are shown on a flip-disc display, the discs all flip over to show the right colors for each part of the picture or word. This happens very quickly, so it looks like the picture or words are moving or changing right in front of your eyes. It's kind of like watching a movie, but instead of a screen that shows moving pictures, it's a board with little discs that flip over really fast.
People use flip-disc displays for all sorts of things, like in train stations to show when the next train is coming, or in airports to show flight information. They can also be used for advertising or even artworks. It's like having a really fancy and cool whiteboard that can show anything you want on it, using cool flipping discs to make it look amazing!