莫比乌斯带
Escher was also fascinated by mathematical objects such as the Möbius strip, which has only one surface. His wood engraving "Möbius Strip II" (1963) depicts a chain of ants marching forever over what, at any one place, are the two opposite faces of the object—which are seen on inspection to be parts of the strip's single surface. In Escher's own words: