You can also tell that the article was written by a mathematician by noticing that the author is Bill Thurston, a very famous mathematician, who we sadly lost a

You can also tell that the article was written by a mathematician by noticing that the author is Bill Thurston, a very famous mathematician, who we sadly lost a couple of years ago. He was amazing. I guess it never would have occurred to me to identify the writing style as mathematician-like in its own right, since I was expecting it to be what it was.