Ms. Kwade, born in 1979, has won international attention in the last few years for her tricky, look-and-look-again sculptures making use of double-sided mirrors, carefully bent copper, and, in one case, a pair of nearly identical Nissan hatchbacks. At the Met, she has limited herself to a narrower palette. Each of the two sculptures consists of three or five rectangular frames of powder-coated black steel, positioned at various angles, soldered together at bottom and rising to staggered heights. On each of these steel armatures lie four or five spheres of colored marble, some sitting on the ground, others balanced on the top of a frame, and a few, bogglingly, suspended in midair.

The works are called “ParaPivot I” and “ParaPivot II,” and they stand independently in the center of the roof garden, inviting you to walk between them and to circumambulate them both. (Alas, you can’t walk inside the frames; though the Met has done what it can to calm the fire marshals, the museum has judged it too dangerous to let visitors get that close, especially with summer cocktails in hand.)

The steel armatures act as picture frames for the skylines of Fifth Avenue, Central Park West, and especially 59th Street — once a street no self-respecting plutocrat would live on, transformed these past few years by an explosion of ultrathin speculators’ condos. Viewed from one angle, the three rectangles of the smaller “ParaPivot II” become parentheses around the El Dorado apartment block on the Upper West Side. The rectangles of the larger “ParaPivot I,” especially while you’re looking south, chop Midtown into morsels of architectural appreciation or financial critique, depending on your view (politically and optically speaking).