...In fact, Escher’s 1922 visit to the Alhambra Palace in Spain was the turning point in his life. He was fascinated and inspired by the spiritual significance of the tile work at the palace, and Islamic patterns played a key role in transforming his art. ...In Islamic art, the spiritual world is regarded as being reflected in nature through geometry and rhythm. Hence, Islamic artists used geometry as an aid to raise their spiritual understanding as well as the viewer’s: “Muslim intellectuals recognized in geometry the unifying intermediary between the material and the spiritual world. These patterns may be seen as symbolizing the Islamic principles of ‘Tawhid’ (the unity of all things) and ‘Mizan’ (order and balance), which are the laws of creation in Islam.” Tessellations are one of the major components of Islamic art. Islamic artists mastered regular division of plane using, in particular, circles on triangular or square grids, because the circle – which has no beginning and no end and thus symbolizes infinity – was considered to be the most perfect geometric form. In mosques, where a wealth of these geometric patterns could be found, one could contemplate the infinite nature of God simply by looking at the walls or ceiling. In short, these geometric forms expressed Islamic artists’ fascination with mathematics as a metaphor for divine order and presence. Escher became fascinated by the regular division of the plane in 1922 when he first visited the Alhambra, a fourteenth-century Moorish castle in Granada, Spain. He then studied Polya's 17 plane symmetry groups, (13 of which are displayed in the Alhambra), and Haag's mathematical definition of the division of the regular plane. But the real metamorphosis in his art began in 1936, with his second visit to Alhambra, which he described as “the richest source of inspiration” in his writings. Like many Islamic artists, Escher believed that repetitive patterns indicated a higher source of knowledge that existed before mankind. He considered order, regularity, cyclical repetitions, and renewals to be the “laws of the phenomena” around us; accordingly, the structure of his designs was a simple reflection of these laws from his own perspective.... [http://www.fountainmagazine.com/Issue/detail/The-Influence-of-Islamic-Art-on-MC-Escher]