The Dutch printmaker M.C. Escher is one of the few twentieth-century artists who became almost universally known by the general public from the 1960s on. Constructed as visual paradoxes with impossible architectures, vaulting perspectives, and dramatic metamorphoses of form, his images startled. Once seen, they stamped themselves indelibly on the memory. I’ll hazard a guess that most of us can recall the amazement of first seeing an Escher image: perhaps Other world (1947), a wood engraving of a pigeon perched beneath a colonnaded arch, seen from three divergent perspectives simultaneously; or the lithograph Drawing hands (1948), where a pair of convincingly rendered three-dimensional hands seemingly sprout from a page, each one drawing the shirt cuff of the other; or Day and night (1938), a flock of geese flying evenly in diametric directions over a Dutch landscape, half of them silhouetted against daylight while the other half transmute into white, set against a nocturnal view of the same scene.