Bathtub Water as a Screen.

Forget about 4K TV for a moment: This augmented reality game uses water — colored white here — as its screen and your hands as the controllers, perfect for in-bath entertainment.

Developed by a four-person team at the Koike Laboratory at the University Electro-Communications in Tokyo, the AquaTop Display is completely interactive and based the movements of your fingers in the water.

“In Japan, the bathing culture is very prominent and so is the use of products,” say the AquaTop developers on their website. “The idea came from the use of commercialized bath salts that cloud the water. The surface of milky water can then be used as a projection surface. The more cloudy the surface, the more clear the projected images are.”

Here’s a pulled-back view of the tech used:

It’s not that complicated, really. Using a projector, a PC, and a motion-sensing Microsoft Kinect camera, in-water gaming, or any sort of programming you’d like to watch while wet, can be a reality.