I mentioned in an email message to the Twain-L listserv how impressed Twain was in one particular unattributed painting.
In another place we were shown a sort of summer arbor, with a fence
before it. We said that was nothing. We looked again, and saw, through
the arbor, an endless stretch of garden, and shrubbery, and grassy lawn.
We were perfectly willing to go in there and rest, but it could not be
done. It was only another delusion—a painting by some ingenious artist
with little charity in his heart for tired folk. The deception was
perfect. No one could have imagined the park was not real. We even
thought we smelled the flowers at first.
I was curious as to what specific painting this is and who the artist is. One respondent suggested that this comment was only "a little dig" at the perspective technique of trompe l'oeil and did not actually refer to a specific painting. I still wonder.
The phrase, trompe l'oeil, is Baroque but the technique is ancient. Examples are known from Pompeii and from ancient Greece. With the return of realism during the Renaissance and it's understanding of perspective drawing the technique came into use in frescoes and ceilings. Twain is known to prefer Renaissance realism over the art of "the old masters".