<P> Escher's work is inescapably mathematical . This has caused a disconnect between his full - on popular fame and the lack of esteem with which he has been viewed in the art world . His originality and mastery of graphic techniques are respected, but his works have been thought too intellectual and insufficiently lyrical . Movements such as conceptual art have, to a degree, reversed the art world's attitude to intellectuality and lyricism, but this did not rehabilitate Escher, because traditional critics still disliked his narrative themes and his use of perspective . However, these same qualities made his work highly attractive to the public . </P> <P> Escher is not the first artist to explore mathematical themes: Parmigianino (1503--1540) had explored spherical geometry and reflection in his 1524 Self - portrait in a Convex Mirror, depicting his own image in a curved mirror, while William Hogarth's 1754 Satire on False Perspective foreshadows Escher's playful exploration of errors in perspective . Another early artistic forerunner is Giovanni Battista Piranesi (1720--1778), whose dark "fantastical" prints such as The Drawbridge in his Carceri ("Prisons") sequence depict perspectives of complex architecture with many stairs and ramps, peopled by walking figures . Only with 20th century movements such as Cubism, De Stijl, Dadaism, and Surrealism did mainstream art start to explore Escher - like ways of looking at the world with multiple simultaneous viewpoints . However, although Escher had much in common with, for example, Magritte's surrealism, he did not make contact with any of these movements . </P> <Ul> <Li> <P> Forerunner of Escher's curved perspectives, geometries, and reflections: Parmigianino's Self - portrait in a Convex Mirror, 1524 </P> </Li> <Li> <P> Forerunner of Escher's impossible perspectives: William Hogarth's Satire on False Perspective, 1753 </P> </Li> <Li> <P> Forerunner of Escher's fantastic endless stairs: Piranesi's Carceri Plate VII--The Drawbridge, 1745, reworked 1761 </P> </Li> </Ul> <Li> <P> Forerunner of Escher's curved perspectives, geometries, and reflections: Parmigianino's Self - portrait in a Convex Mirror, 1524 </P> </Li>

What type of intricate hand work is seen in the image above