Procrustean—what does the word even mean? In Greek mythology, Procrustes was the son of Poseidon, and a thief who tortured his victims by making them lie on an iron bed. If their bodies were too long, he’d cut off the oversized bits; too short, he’d stretch their limbs to fit. Both procedures were fatal, and, Goldilocks-style, few victims fit the bed. “Procrustean bed,” the idiomatic phrase in which the word is most often used, denotes an arbitrary and brutal standard. Yet conformity—aesthetic, thematic, or otherwise—is not what a visitor gets from Welsh artist Sebastian Jefford’s exhibition in Gianni Manhattan, a skylit, subterranean space in Vienna’s third district, open since January 2017 and arguably the most daring and international of the city’s crop of new galleries. Hung on the wall beside the downward metal ramp leading into the gallery is Aggressively Indeterminate Biscuit (all works 2018). It’s arresting enough to make me stop. The core of the sculpture appears to be a flattened cardboard box, overlaid at its edges with thick, bulbous protrusions clad in patchworked sheets of gray polyurethane foam, their surfaces indented with what appear to be shoeprints and studded with the colorful, plastic snap-fasteners found on jaunty sportswear. On the …