Why was that dog/bunny puzzle at the top of HN's frontpage yesterday? How were so many people entertained by it, when a computer could have solved it in microse

Why was that dog/bunny puzzle at the top of HN's frontpage yesterday? How were so many people entertained by it, when a computer could have solved it in microseconds? Humans like puzzle games, for some intrinsic reason. Chess is a very large and addictive puzzle.