"By the early 16th century," "European painting had advanced to a position of mastery." "At a time of fast-developing exploration, it was prized for its ability to collect and display the contents of the known world" "in the most vivid fashion." "Emphasis was laid on painterly artifice the tricks whereby artists could conjure up an illusion of three dimensions." "The most prized illusions were those achieved through the principles of perspective." "This strict rules of perspective arose out of a desire to systematise representation," "by analysing the processes whereby the eye construes forms spatially." "This diagram, from a painter's manual, suggests how a shape on the floor is projected onto the retina." "It is as if threads were to link each corner of that shape to the viewer's stationary eye." "Drawing the threads taut, the viewer realises a perfect geometrical relationship to what is visible," "but such a perfect relationship almost cries out to be subverted." "The meticulous mechanism of perspective is something that can also be tampered with." "An object, such as a chair, set strictly in perspective, may be shunted just as strictly out of perspective." "In ordinary circumstances, our gaze is free to roam in space across the changing aspect of objects, gauging their true shape." "That is why our eyes can normally guide us safely through the environment." "The effects of anamorphosis rely on forcing the eye to look out from a single fixed point, such as a peephole." "This 16th-century woodcut offers a fascinating visual puzzle." "Only by turning the picture sideways can the viewer make sense of the image." "The celebrities of the age lie concealed amid a perplexing array of nonsensical forms and misleading diversions." "In this second woodcut, we are given easy access to the scene of an old man embracing his young wife." "Initially withheld, a second meaning emerges into unmistakable focus." "Out, you old fool!" "The young wife has now made her choice of lover." "As well as hiding secrets in the secular world, anamorphosis can enhance the mystery of the numinous." "In this anonymous religious painting, peepholes bored through the side of the frame" "direct the eye to the holy images hidden within the confusion." "(Birds call)" "(Creaking)" "(Waves lapping)" "(Bell tolls)" "Crammed with visual red herrings, this picture might be thought to parody the fumblings of the spiritually blind." "There is only one way to true vision." "Painted on the wall of a cloister in Rome, a 17th-century landscape with pilgrims, ships and towns" "is overwhelmed by incoherent shapes." "Anamorphosis is a most powerful device for controlling understanding." "It may be used whimsically, to amuse, or else it can provoke and instruct." "An image grasped too quickly might not leave a lasting impression." "To lead the eye slowly through incomprehension and then to offer a resolution - that is insight!" "Anamorphosis thrives on mystery, and its masters rarely give away their secrets." "Here, we peep at the apparatus which Emmanuel Maignan supposedly used" "to construct his anamorphic fresco of Saint Francis." "If anamorphosis is the art of delaying access to deeper meaning, then we must learn to wait for revelation." "(Bell tolls)" "The Ambassadors a mystery in two acts." "On one level, Hans Holbein's famous painting is a gorgeous display of enviable riches." "Well-nourished and confident, the ambassadors pose beside the emblems of their knowledge and worldly authority." "The artist is thought to have conceived his picture with a doorway to the right," "guiding the viewer to a final observation." "The anamorphic skull is a hidden signature, for Holbein's name means hollow bone - "hohl Bein"." "The skull is a sinister commentary upon worldly vanities." "Death lurks beneath the most luxurious surface." "The visual trick of anamorphosis conceals, then discloses the truth which underlies appearances."