I’ve long loved the weird mechanical purring of those flappy-letter signs one sees (or at least used to see) in train stations & similar venues, but I haven’t felt like throwing down the better part of three grand to own a Vestaboard. Now maker Scott Bezek is working on an open-source project for making such signs at home, combining simple materials and code. In case you’d never peeked inside such a mechanism (and really, why would you have?) and are curious, here’s how they work:

And here, for some reason, are six oddly satisfying minutes of a sign spelling out four-letter words: