What else could you install at the center of a traditional circular staircase than a hanging light art piece? 'Starlight', by Cooper Joseph Studio, on show at the Museum of the City of New York, is bright and graphic, light and poetic, simple and impressive. Walk a step, and it's a new pattern that appears. Walk up the stairs, and you're wrapping the sculpture as a movie camera would. Extend your arm over the handrail, and you're in the middle of a web of fireflies. This sculpture perfectly uses its environment to propose an interesting experience to the visitor. Its scale makes the changing graphic patterns very readable and almost hypnotic. The idea is very simple but how efficient?!