I’ve seen these all over Europe. Some have simple images of the cross flashing, some have windows screensaver esque animations, and some have 3d renders of various things rotating in all sorts of ways. Why is that? Wouldn’t a simple green cross be enough to get the point across, or do they need to be overly verbose? Here’s the full video instead of a gif
I’ve seen a colour one like the one I posted below here in Portugal. It really is not an institutionalised thing, it’s just what the owner decides how wacky their place is gonna be.