This apparatus lets you make carefully timed droplets, synchronized with flash, to make images like this one. The apparatus was built by Kyle Hollis and Kyle Walters in 2016, as an Independent Study project. Here is an instructional video showing how to get it ready to use: https://vimeo.com/251386374
Here is their quick start guide, followed by the full detailed report: DropSplash QuickStart and Documenation