The Bookworm street art illusion was created by Gregor Wosik (1955 –), a Polish street artist who presented his artwork in Mönchengladbach Rheydt, Germany in December 2015 (see Wosik).

Bookworm is one among a large number of anamorphic illusions in which a cleverly constructed two-dimensional painting looks like a three-dimensional object either when seen from the right angle (in perspective forms of anamorphisim) or when viewed with a mirror in the right location (in mirror forms of anamorphism).

A famous early example is found in Hans Holbein the Younger’s The Ambassadors. When viewed from the bottom right, the otherwise distorted image in the bottom of the picture reveals itself to be a skull.

When viewed from the right perspective, the distorted skull in the middle should look like this
This video from “bruspup” shows how powerful anamorphic images can be:

https://www.youtube.com/embed/tBNHPk-Lnkk

You can download and print out some of the images used in the video to re-create the effect for yourself. (See below.)

Perspective forms of anamorphic images are usually forms of ambiguous figure because while one can be fooled and experience the anamorphic images as 3-D objects, one can also often see them as distorted 2-D images. Unlike ordinary ambiguous, such as the duck-rabbit that you can see on the Illusions index, perspective anamorphic images require that you see the image from a particular angle.

The mirror form of anamorphic images have been explored extensively by artist István Orosz. Two example of his are below. The second example is his most famous work, called Mysterious Island. A picture of author Jules Verne emerges when a cylindrical mirror is placed in the right location.
Anamorphic images beautifully illustrate the fact that the light that falls on our retina, and the subsequent visual experience that you have, could be produced by a large number of different arrangements of objects and properties in the world in front of you. Both a 3-D object and a 2-D image can cause the same light to fall on your retina, which can then cause the same experience. When we look at ambiguous figures, our experience can flip and we can have an experience of two seemingly different things. In the case of anamorphic images, we can expereience at different times an apparent 3-D object (which the anamorphic images fools us into having) and what is really there (the 2-D picture).

Anamorphic images also raise the philosophical question of whether we ever really directly see the way that the world is, or if we only really see an image or representation of the world that is generated in our mind (a sense-datum). See Crane & French (2016) for discussion of sense-data and related issues.

Below are a couple of anamorphic images that you might want to print out to recreate the effect in the video above.