An optical illusion

As a child I remember looking through an art book of work by M C Escher. I was completely transfixed and that fascination with the finding of hidden details or clever optical illusions has carried over with me into adulthood. The small sample below are free images from Pixabay. If, however, you fancy a darker variation I am more than a little partial to the deviant art of Jeff Lee Johnson here...don't say you haven't been warned though! https://jeffleejohnson.com/site/Rue_The_Day.html

Arilx