SPREAD OUT ON THE MALT BROWN FLOOR of the Renaissance Society this summer were 110 equilateral triangles of indigo doth partially sewn together in a segmented field: Helen Mirra's Sky-Wreck, 2001. Responding to the architecture of the space, with its vaulted ceilings, metal bracings, and polyhedral floor plan, the triangles were interwoven as interdependent hexagons, pyramids, and parallelograms—something like a complicated chemical notation. The cloth panels were linked in a winding chain; Mirra stitched along one, two, or three edges of each triangle, rendering the whole assemblage a