The Amazing Two-way Fore-edge Book Painting

What is doubly amazing about this fore-edge book art is that the page block can be fanned in the opposite direction and a second painting discovered. Fore-edge art is a painting on the gilded edge of book. The book is fanned and a picture painted on it. When the book as relaxed back to its normal position the image disappears and when refanned, the painting magically re-appears . This is an old antiquarian book art, which has been reborn by modern specialist fine artists, such as Martin Frost