Anamorphic pictures are drawings and paintings which appear distorted and almost unrecognisable to the unaided eye. However, when they are viewed from a particular perspective, or using a ‘decoding device’ they are easily interpreted as recognisable images. Anamorphic Art has a long history, having roots in many cultures around the world, including China, England, France and the Netherlands. Distorted images were used for everything from amusing royalty, to carrying secret messages and concealing political allegiances. A particularly good example of oblique anamorphosis may be found in the National Gallery’s The Ambassadors by Hans Holbein the Younger. Oblique anamorphosis is closely related to the artistic technique trompe l’oeil.