The 4 bit square root circuit shown in the video was made using 3D printed parts. I was using one of the early 3D printers (RepRap Huxley), and found that the parts weren’t reliably watertight, so I painted the insides with enamel paint to waterproof them. After the paint was dry I applied a hydrophilic coating to help prevent drops adhering to the surface, I used a car windscreen anti-fog liquid for this (Rain-X Anti Fog). I didn’t apply a hydrophilic coating to the top bend of each siphon, to prevent capillary flow through the siphon. An acetate sheet was glued to the front of each siphon, but not to the channels connecting siphons together. The image below shows the construction: