Most people don’t look for hidden pictures on the edges of books, but years ago “fore-edge paintings” were an elegant embellishment to printed works.
Reaching the height of popularity in the 18th and 19th centuries, these paintings were invisible when a book was closed. To see the illustrations, one would have to fan the pages ever so slightly.
The Historic New Orleans Collection recently acquired a book from 1849 with a rare double fore-edge painting. When fanned in one direction, a view of Philadelphia emerges; fanned from the other direction, a scene of the New Orleans riverfront appears.