Google loves color, there's no disputing that, and it's obvious they want to add as much of it as possible into the Android operating system which is displayed by the vibrancy of Android Lollipop. Google also loves exploring new technological ideas and implementing those ideas into potential future projects in hopes of them taking off. A recent patent awarded to Google showcases they're looking into developing some sort of screen tech which aims to give your phone screen more color. Not while the screen is on mind you, because there's plenty of color to see in this state. What the patent aims to do is make it possible for your phone's screen to match the color of your phone when the display is off.
This is still just a patent of course, but Google could definitely already have research teams working on development. The patent describes a tech that would be a layer that sits under the glass of the screen but above the actual display, described as a "color changing layer," which would essentially turn your phone into a colored slab when you're not using it. It's an interesting take on bringing something new to the smartphone world, and while it may sound a little gimmicky as it certainly serves no advanced functional purpose, it's something different which hasn't been done before and plenty of consumers would probably find it amusing. It would also serve as a new means of customization of the device.
It goes without saying that the phone display would appear as normal during use, so you would simply see the Android software UI you see now when you interact with your phones. In addition to the color layer under the screen, it appears Google wants to possibly take things a step further and have the same color changing layer applied to the outer phone body as well so the color could be changed by the user, which would in turn also change the color of the screen again to match the phone body. Keeping the phone screen in a constant state of appearing as whatever color the phone happens to be would need battery power, and Google explains in the patent that the battery would feed a small amount of power to the color changing layer for this particular function. Some may see this though as just another thing to drain the battery on their devices, and battery life is already a main issue for many users. Whether or not this ever makes it into production ready devices remains to be seen, but should Google take the tech and run with it, there could one day be new devices which have a chameleon-like outer shell.