I still think in APL, and every once in a while I try to RosetaStone those ideas into k or q. (Apologies for using RosettaStone as a verb, all the cool kids seem to be using nouns as verbs now)
My latest APL to k/q quandary is trying to get "covariance contracting for commodities" (or maybe it's "commodities covariance contracting") to work in k/q. ( It's a real thing, you can look it up).
I also have an old APL function (old as in STSC pcdos APL transliterated into Dyalog6 only recently redefined as a dfn) that prices options on an auto-correlated underlying asset using a binomial tree, (I was going to spring that on MortenK as a last-minute entry to this year's Dyalog conference in Portugal, which unfortunately is not to be) ... I'd like to get comfortable enough with k & q so I could dash that off in k & q without transliterating from the APL. And I'm sure I will be that comfortable with k & q ... "any day now"
And then of course, there is the APL function that implements "Varianza Gamma senza lacrime, senza piangere." (which I'm keeping in my back pocket until there's a kx or Dyalog conference in Italy) ... Again, there's the inertia of having already worked it out in APL and trying to engage my mental Rosetta Stone to put it into k/q.
But my working through NickP's "q-tips" seems to be going well, so hope springs eternal.