In my online undergraduate P5.js course, students are about to begin the module on motion and physics, including a bit of physics simulation using Matter.js. It suddenly occurred to me that I had never seen anybody put together this particular demo before, and I realized it had to be done. Messy source code at https://editor.p5js.org/isohedral/full/vJa5RiZWs.
@csk also, recently I said I'd been nerdsniped and one of my younger colleagues asked what I meant; I dropped a link to https://xkcd.com/356/ and then realised it's *19 years old* (so is the "I know regular expressions" one)...so came out before he could read...how did we get so old? A warning for showing this to students ;)
Nerd Sniping

xkcd
@bazzargh @csk https://xkcd.com/435/ My favorite, which I regularly show my physics students.
Purity

xkcd