What interesting problems have you solved recently?
To go into specifics of actual problems solved and do so intelligibly, I'd have to provide specific context, which I'm not comfortable doing here.
It's a lot easier to describe "interesting problems solved" using less identifiable (and more generally interesting) details if one is in platform/infra and/or operating at a Staff+ level -- both of which I have been in the past (and loved it), but am not at the moment.
It's not worth the internet points for any of us to post details beyond what we do.