M. C. Escher

For me it remains an open question whether [this work] pertains to the realm of mathematics or to that of art.
– M.C. Escher

M.C. Escher's "impossible figures" inspired mathematician Roger Penrose whose fruitful collaboration with Stephen Hawking led to the "Penrose–Hawking singularity theorems", essential to demonstrate the existence of "Black Holes" and explain their paradoxical ("impossible") behaviours.Indeed (Source: Impossible object (Wikipedia)):

In 1956, British psychiatrist Lionel Penrose and his son, mathematician Roger Penrose, submitted a short article to the British Journal of Psychology titled Impossible Objects: A Special Type of Visual Illusion. This was illustrated with the "Penrose Triangle" and "Penrose stairs." The article referred to Escher, whose work had sparked their interest in the subject, but not Reutersvärd, whom they were unaware of. The article was only published in 1958.

Links:

• M.C Escher (Simply Art)
• The Mathematical Art of M.C. Escher
• Impossible World
• Maurits Cornelis Escher: His Influence in Math and Art
• Beyond Escher for Real