New Yorker writer Ian Frazier has a mild fixation with plastic carrier bags. Over the years, he has become transfixed by the sight of them billowing, tattered and water-logged, in the bare branches of New York’s sidewalk trees, along with several hundred tangled metres of cassette tape. Understandably, he loathes the ugliness of this spectacle and, with a friend, invented a device, a sort of hooked pole, with which to unsnag stuff from trees. Their success (they even patented the pole) led to a brief flirtation with a similarly cunning invention with which to bring helium balloons down to earth. They were inspired by the irritating sight of one of those silver heart-shaped birthday balloons apparently stuck forever to the ceiling of Grand Central Station, dancing across its mural of the constellations.