Researchers at Akishima Laboratories (Mitsui Zosen), working in conjunction with professor Shigeru Naito of Osaka University, have developed a device that uses waves to draw text and pictures on the surface of water. The device consists of 50 water wave generators encircling a cylindrical tank 1.6 meters in diameter and 30 cm deep (about the size of a backyard kiddie pool). The wave generators move up and down in controlled motions to simultaneously produce a number of cylindrical waves that act as pixels. The pixels, which measure 10 cm in diameter and 4 cm in height, are combined to form lines and shapes. The device is capable of spelling out the entire roman alphabet, as well as some simple kanji characters. Each letter or picture remains on the water surface only for a moment, but they can be produced in succession on the surface every 3 seconds.
I don't see a use for this but at least it looks cool. And once we perfect writing on water we can work on more important things. Like writing on the moon. With a giant laser. To carve my name.