That can arguably be attributed to experience and cleanliness.

If you walk into a garage it can be dirty, greasy and disorganized. It can also be labeled, clean and organized. Hardly considered art

Code or art?

http://www.ioccc.org/2013/birken/birken.c

Ok. Yes its asthetically pleasing. I feel comfortable looking at it. But...

its completely unreasable because all the variable names have been mangled and there is no whire space to organize the blocks. At this point it looks like a puzzle.

If you consider the algorithm an art, I disagree. Algorithms are either more efficient them their predecessors or are efficient for a niche.