Nil Yalter’s latest show, “Kara Kum” (Black Sand), dwelt on the idea of transformation. It started with a prologue. Visitors heard a recording, emanating from behind a curtain with a kaleidoscopic print of images, of Yalter’s voice uttering words in Turkish, English, and French that relate to themes such as time, space, darkness, and movement: “dark matter, atomic nucleus, volume, hidden.” This work, Untitled (all works 2018), is a distillation of a five-minute-long performance; some hourglasses the artist had used during that piece sat on a table in the middle of the room. The black sand, or