Just pure, simple, easy style. There's nothing here but knits and purls to give a classic fabric that's simple to make, but has very flattering lines. Armholes are curved in and sleeve caps are nicely rounded to accommodate layering; shoulders are sloped too. There's a crewneck option with three buttons, or the V-neck with one button closure. Instructions for each are given completely separately, for less confusion with the excellent size range.
