|Golden Ratio bracelet from Kokoba|
This one is only from 2013, probably, so it's not super old. (Old enough for a #tbt post, though!) To be honest, I don't know if it's worth it to focus on any irrational number except pi? I did get a custom request for the square root of 12 a couple years ago, but pi is usually the rock star of the math world.
What do you think, mathematicians? Is pi the only irrational worth knowing, or should I strive to go full hipster and highlight some of the more obscure irrationals?