The two layers on G&W Pinball remind me of the modern IGT video slots (at least in Australia with the BlueChip Neo/Neo-N machines, no idea about US etc.), they use a 3D LCD monitor to do a similar thing, the virtual reels are usually displayed on the back layer, but when you get a winning line the symbols are displayed on the front layer and made larger. It's basically a transparent LCD on top of another LCD.
