That sounds like a great way to do it; if I were an applicant, I would have liked process. (I am currently looking for jobs, and do have a recent experience of an on the spot test which I just hated).

I thought I'd try your step #2: I have no idea of the wall follower rule, and no prior experience in maze solving, but did bring it home in 18 minutes.

That included figuring out this particular Blockly UI (have admittedly seen similar UI with Dash and Dot, only at a much simpler level of doing non-branching, sample tutorials with my 6 year old boy), trying to design a simple program, reaching some dead ends / observing effects, and then realising what needed to be fixed.

I did use all the blocks for 17 lines of JS though, so perhaps better ways to do it, but thanks for that interesting little challenge at any rate. :-)

I'm guessing really smart people would have it done in just a few minutes.. Also monitoring son's cough (night time in Australia) to make sure it didn't get worse, for a bit of distraction.

(Edit: Brought it down to 1 spare block / 16 lines having a 2nd look after writing this comment.)