Anamorphosis

Anamorphosis is a technique in which an image, or the production of an image, appears distorted unless it is viewed from a special angle or with a special instrument. This is a rather obscure form of steganography, but it has been used in the past and deserves mention. The word anamorphosis is Greek and means "change shape." It is meant to imply a transformation the viewer effects by shifting his or her perspective (Figure 2.2).

Figure 2.2