I'm not convinced by smithsax's neat definition, although I can understand it being used in such a way (the Chambers entry is more problematic).
For fyellin the 2nd person is a complete unknown but he caused a bit of a stir over here, in large part because of what he did and what he achieved (that probably says something about the British class system). He even suggested that what he did had helped him achieve it - and he continued doing it afterwards.
For this reason the puzzle - as good as it is - seems to be a lost opportunity, if the trajectory had simply been reversed (starting with B and ending with A) we'd have a neat symmetry and 'art' emulating life quite beautifully... unfortunately, the palaver with the circled cells precludes an easy reversal.