"If what AARON is making is not art, what is it exactly?"
AARON is a computer program written by artist Harold Cohen. It was designed to autonomously produce art, originally as abstract drawings, that grew more complex over the years and with images of rocks, plants, and eventually also people and interior scenes later on. Cohen also used machines to produce physical artwork.
You can learn more about AARON and its author on Wikipedia and the author’s website. There is also a Twitter bot that appears to be either posting new artwork or artwork inspired by AARON’s style.
