After the white-hot blast flashed across the sky, after the air turned toxic and we all zipped ourselves up inside government-issued suits like garbage bags, our breath misting on the clear plastic squares that let us see through our hoods, I started watching Jay. He’s always been across the street, as much a fixture as the maples lining the sidewalks before the flash, before everything burned and the trees became charred silhouettes. After school, Jay used to push the mower in neat rows across the front yard while I sat on the porch with my homework. That boy walking toward…