It's all about the contour cut, or more accurately the layering of sculpting cuts like the contour lines of a map. Here you can see see blanks firstly marked from a fine board of walnut, then stages of 'layer cuts' in order to arrive at the desired seat blank shape. It is 1 thing to draw a line, another to begin cutting away to reveal or 'release' the form within. In order to do this each layer cut is visualised then removed before being layered on to the next set of cuts until eventually - it looks really good. (Subjective, yes), however one instintively knows when something just, looks correct.