Someone ends up rediscovering it every few months, so I like to think of it as an HN tradition. It's also a sign that HN is growing as a community, which is good or bad depending on how you look at it!
This would never fly at my bank. They really should've used the observer pattern for the divisibility tests.
It's... so..... beautiful!!!! I cant, I can't breathe anymore...
I clicked through all the interfaces, seems extensible.