The order of adjectives

Why is it that we can say “a beautiful large old square blue Persian rug”, but not “an old Persian square blue large beautiful rug”? With just a few exceptions, adjectives must appear in a set order, which we all intuitively know as speakers of the language?
http://www.bbc.com/culture/story/20160908-the-language-rules-we-know-but-dont-know-we-know?ocid=ww.social.link.email