Is it an innie or an outie?

I like this because it’s simple, and it exists in the real world, as a detail of the Palace of the Legion of Honor, at the Fine Arts Museums of San Francisco.

I wonder: was the architect consciously aware that he was creating a visual illusion?

Here’s another view of the architecture, with more of the surroundings, by a different photographer.

By the way, it’s an innie.

– Optical Illusion By David Gallagher, Flickr>>
– Optical illusion, Bryan Costales, BCX>>