Here’s an ad that actually promotes Stendhal Syndrome, a psychosomatic disorder in which you hallucinate that you are within a work of art.  The text reads, “Are you inside or outside this picture?  Something to think about!”  From Popular Mechanics, 1930.

I stumbled across this work of genius! It made me smile so hope it  adds to your day also (who ARE you talking to? ED) personally I think I am hiding behind the tree just visible through the window! I studied some aspects of synaesthesia whilst at college which I believe to be similar or related in some way in that Francis Picabia was said to suffer from it (the syndrome of seeing sounds, smelling colours etc) and my thesis was that it may have been inspired by opium in Picabia's case.

Francis Picabia - Self portrait

Picabia - this painting perhaps more than any other shows the idea of synesthesia