The work is flat in its width, but curved (concave) in its length. It’s the sort of thing you’d think you’d want a compass plane for. So, the work is wider than the shave, but curved. Think of the upper and lower supports on the back of Paul’s rocker, the pieces that all the slats go into. In fact, I looked at Paul’s video in which he is fairing the curves on those supports and noticed that he is only getting narrow shavings, which is what made me wonder if he has sharpened a camber across the width.