Santiago Mostyn has placed low banks of sand at rhythmic intervals throughout the large, open exhibition space of Södertälje Konsthall. Brazil nut casings lie scattered on top of the sand; they are also suspended from the ceiling, each shell holding a speaker. A soft clicking animates the room, as the eighteen-channel sound work emanating from the shells thickens the space at the periphery of my senses, like a subliminal awareness of thriving insect life. Looking down, I notice that viscous liquid fills one of the empty shells to resemble brackish rainwater trapped at the bottom. One shouldn’t leave water standing in the tropics, it invites mosquitoes to breed, I think, and realize that my mind has left the outskirts of Stockholm. The floor beneath Mostyn’s piles of sand is a permanent artwork by the design duo Laercio Redondo and Birger Lipinski, entitled Opacity (for Édouard Glissant) (2021). Inspired by indigenous weaving techniques in the Americas, it is an abstract geometrical pattern made with rectangular flooring panels in beige, navy, and powder blue. The design reminds me of a disarticulated Catholic labyrinth, a geometric pattern inlaid in stone on the floor of cathedrals during the Middle Ages, that provided a score …