An grid of very small electromagnets at the back of the frame turn on and off to hold iron filings in place in the shape desired to form a picture. When the frame rotates, the magnets turn off and the iron filings drop to the bottom of the water filled space until the frame is turned upside down, at
which time the magnets turn on in another configuration to form another picture.
The pictures could tell stories. You could have writing as well, but I think just having the series of pictures telling a story would be more interesting.
See link for the hydro / mechanics behind the ides. You basically just add the magnet grid to that and use metal filings instead of sand. The magnets could even make a layer with holes in it like the models shown.
And to some extent, these could be animated as well. Actually, might be interesting to have the water constantly swirling instead of the frame turning. You'd see a picture, then it would disintegrate into a tornado of particles then reform to the next picture.
The pictures could change a section at a time as well. Person standing on one side talking to a person on the other who disintegrates and turns into a bird. I've seen animations that just have one thing that morphs into another and another and another. This would lend itself to that.