This water is so smart, it can solve a maze. (Skip ahead to 1:19 if you want to avoid spoilers and just be amazed.)
The secret is the Leidenfrost Effect, the same phenomenon that causes a drop of water to skip around on a hotplate without actually evaporating. By putting sawtooth-shaped surfaces on the edges of the maze, and heating it above the Leidenfrost temperature, the water droplet can find its own way through the maze (via IFLS).
That's all for this week. See you on Monday!