Maçka Sanat Galerisi, a tiny gallery founded in 1976 by sisters Rabia Çapa and Varlık Yalman, has been very influential in the Turkish art scene. Its remarkable story deserves a longer article, but its importance should be at least briefly mentioned in any review of “Variations,” Füsun Onur’s recent exhibition there, for the gallery’s peculiar architecture has long influenced the work the artist has shown in the space. All its surfaces are covered with light-brown tiles; over three decades, Onur has sometimes treated this grid as a mathematical graph or as music paper, as in her quiet installations