No, it’s an optical illusion - both shapes exist, but different groups of people tend to see one first instead of the other.

I see the rectangles initially, but after staring at the cross for a bit the circles appear:

Good call - not sure you can tag images in comments as NSFW (to get the auto-blur), but I’ve hidden it in spoiler tags.

(Potentially) [NSFW]

Edit: This one’s been floating around the net for long enough that I’d forgotten what the feathery chap in the back left was up to!

Hidden behind a spoiler for those who don’t want to see an owl swallowing an entire rat(!)

Parents would find their baby child had been replaced by odd beings who were almost but not quite human.

However strange appearances aside it was their behaviour that marked them out - changelings were said to be either extremely badly behaved - constantly crying and prone to violence, or at the other end of the spectrum strangely docile, often mute and seemingly unable to comprehend anything about the human world they had been left in.

https://www.hypnogoria.com/folklore_changelings.html

Yep, totally a brand new thing that hasn’t appeared throughout human history.