Tufte (2001) and Wilkinson (2005) emphasize a lot on the aesthetics of graphics. There is indeed more to graphics than mere mathematics, and the subtle changes/corrections in a display may lead to an improved, enhanced, and pleasing feeling on the eye diagrams. Wilkinson emphasizes on what he calls grammar of graphics, and an R adaptation of it is given by Wickham (2009).
Thus far, we have used various functions, such as
plot, and so on. The grammar of graphics emphasizes that a statistical graphic is a mapping from data to aesthetic attributes of geometric objects. The aesthetics aspect consists of color, shape, and size, while the geometric objects are composed of points, ...