Mathematician Matt Parker built "what we suspect is the world's slowest computer" using dominoes—10,000 of them, to be exact. He and a team set up the massive computing system to do extremely basic computing tasks (specifically, adding numbers) by laying out "circuits" of stacked dominoes.
The domino-based computer was then set to work; for each configuration it only gets one go, as the dominoes need to be re-stacked to try again. The team tried adding the numbers 4 and 6. They got 10! It worked!! Computer science for the win. (Then they did it again, making it a bit more complex, so a new configuration could add larger numbers using the same set of dominoes. I'll let you see how that worked out.)
If you like math, dominoes, and/or solving problems the hard way, this video is for you.
For more details on binary math, and how the domino computer works, watch this Numberphile video: