A graphical waterfall is a display where images are formed by water droplets falling from computer-controlled nozzles. It was invented in 1977 by Stephen Pevnick, an American artist. Graphical waterfalls can be used with regular lighting (as on the left video) or with a stroboscope (as on the right video), depending on the desired effect. It is unclear whether such devices have been already used to display data. Sources: Pevnick Design (2018), Invention of the Graphical Waterfall®. Wikipedia, Stephen Pevnick.

While volumetric displays have a long history dating back from the 1910s and are still an active topic of research, the improvement and democratization of LED technology made it possible for anyone to build low-resolution volumetric displays by arranging many LEDs in a 3D matrix. Today, hundreds of video tutorials and demos of LED cubes can be found on YouTube (the left image is from a 2021 tutorial). Perhaps one of the earliest people to come up with the idea was artist Todd Holoubek, who built a LED cube back in 2002 (right image). In an email, he tells us: The led cube was a collaboration between James Clar, Cindy Jeffers, Danielle Lee, and myself. It was a final project in the spring 2002. We had seen nothing like it. The inspirations were 2D led art from the likes of Jim Campbell and the emergence of 3D visualization technologies which were becoming popularized through Siggraph and the mainstream media. This was a little before the maker movement, on-line information about leds and led technology was very scarce. We did the best we could with the skills we had. Sources: Todd Holoubek (2002) LED Cube v1 Quote from Todd Holoubek in an email from April 2018 Left image: Dave Rowntree (2021) Big RGB LED cube you can built too Right image: Todd Holoubek, see first link above.