It’s the 4th of July. In the empty lot by the playground, a group of Bangladeshi teenagers are setting off professional-grade fireworks. Bang, bang! BANG! Bang, whiz. Bang-bang! Sometimes one fails to go off properly; everyone steps back until it’s spent itself into the asphalt. A group of 30 or 40 people, families with kids, black white whatever, watches from a safe distance. A couple of kids on bikes go round and round. At one point it seems like the fireworks are finished; then a group...