I'm pretty sure that Stern was aiming at something like 50 Central Park South (Ritz Carlton New York:
https://si.wsj.net/public/resources/...0612184200.jpg) which starts out rectangular and regular and gets more asymmetrically massed and more varied in style and window openings as it ascends. But he stretched it much taller and narrower and flattened the setbacks so much that they sometimes disappear, and then it just looks like random window groupings. Add to it that Chicago doesn't have any buildings with that sort of language like New York. I understand what he was doing, and there is an inherent, if somewhat obscure logic to it all, but I also agree that it is not completely visually successful.