In Russia we have a saying: “Don’t dig a hole for another because you’ll be the one that falls in it.” I have been very fond of this proverb since childhood when my parents shipped me off for my summer holidays to stay with my Ukrainian grandparents on their farm. There, over a period of three long months, I became friends with a local boy who introduced me to a game that all the kids in our village played. The objective was simple: to dig a hole, conceal it with leaves, branches, and other debris and then guide your chosen target into it—typically a girl you fancied or, better still, a competitor for her attentions. Whoever said chivalry is dead has never been deliberately walked into a hole by the boy of her dreams. Over the course of the summer, the game became more and more elaborate and the risks and rewards spiralled out of control: It turned out Ukrainian adult villagers were not fond of twisting their ankles in holes dug by their offspring …