> Algo/puzzle/riddle is not the same as whiteboard. I'm all for getting rid of the former, but I have no problem getting up and writing on a whiteboard as long as it's used for its correct purpose, viz. as a tool for talking through a problem together.

I agree.

We did a few interviews last year, and we had a few whiteboard-ish (people could do it in their heads if they preferred) questions.

However, the whole purpose of these questions (and this was made explicit to the candidate) was to serve as an anchor for a technical discussion, and as a tool to observe them reason about a problem. And as a way to observe them asking questions, because we were intentionally incomplete (and candidates knew).

I felt it worked very well for us.

Also, sometimes such an interview would just be plain fun for all involved. We took it as a strong signal if that happened.