Becky noticed the round jars of coloured sand on the shelf as she went to look for some chocolate. She hadn’t known why at the time, but she’d followed the impulse to bring a little sand home with her from special places, usually scooped up quickly and a bit furtively in the clear plastic wrapper of a cigarette packet. They were all lined up in little round jars from a disused yogurt making machine in front of her unused cookbooks on the kitchen shelf.