The Recreation: Humor: Wordplay: (Ambigrams Wordplay )

Ambigrams Wordplay Humor Recreation.

The earliest known non-natural ambigram dates to 1893 by artist Peter Newell. Although better known for his children's books and illustrations for Mark Twain and Lewis Carroll, he published two books of invertible illustrations, in which the picture turns into a different image entirely when turned upside down. (wikipedia)