Bycatch from my Snark hunt:
I discovered that “face” in Matthias Grünewald’s painting in 2018, but perhaps I was not the first one. I think that Gustave Doré found it already in the year 1863 when looking for inspiration from other artwork.
2018-09-21, updated 2019-02-19
Artists, who have played with their own paredolia first, know how to play with the pareidolia of the beholders of their works.
I incidentally found this in December 2017 as bycatch from my Snark hunt:
2017-12-23, updated to 2019-01-01 just for the heck of it
2017-09-13, update: 2018-10-11