This simple project ended up being a great way to learn about superhydrophobic materials (and hydrophillic).
Basically, we just seized the opportunity to practice some simple CAD and build a small simple maze from lines and curves. Then we printed and refined a few versions finally using a superhydrophobic spray made by Rustoleum called “Neverwet” (which has been discontinued, sadly) to add a coating to the PLA plastic. The refinements to the CAD were just making the walls higher and adding some fillets to smooth out the surface transitions and make it easier for the coating to bond effectively.
By the end of it we realized a fun element would be to put two different colors of water droplet into the maze at once- we used yellow & blue at opposite ends of the maze, so you’d have to start at the star and try to get to the key without being gobbled by the blue blob which turns you from yellow to green.
Fun.