What are a few principle issues with art and beauty?

Answer 1

http://faculty.evansville.edu/rl29/art105/sum04/art105-13.html

http://www.greeklandscapes.com/greece/athens_museum_classical.html

http://www.hellenic-art.com/pottery/

http://arthistorystudents.files.wordpress.com/2007/10/pieta_small.jpg

http://www.quinnevans.com/images/photo_wren_chapel_large.jpg

So what do you see in common in those works of art? What principles? Symettry? Simplicity?