A British sculptor known for her casts of architectural spaces is invited to create a public artwork in New York City. After traversing the metropolis in search of inspiration, she notices the “weird wooden barrel-like objects” that sit atop many Manhattan buildings. At first the artist has no idea what purpose these structures serve (to supply water to sprinkler systems) but they intrigue her. She decides to make a 12-foot-high translucent resin cast of the interior of one such tower and install it on the roof of a building in SoHo near the corner of West Broadway and Grand. Not only does the translucent material evoke water, but it proves beautifully responsive to the weather: on cloudy days it almost vanishes; against a blue sky it glows; at night, it becomes, as the artist puts it, “like a sort of smudge.” Unfortunately, at the end of its time on the roof the sculpture is acquired by a museum, never again to be exposed to the elements, never again to display the mutability that was its most notable quality.