It starts as a faint whiff of horse sweat and stables. On Spring nights when I walk home from the subway through our compound in Shanghai, I can map where I am in relation to the jasmine vines surging over the rockeries. Under lantern light, these boulders look as though they are capped with snow. From twenty feet away, the scent is seductive – a mix of barely-ripe banana, paperwhites, and pony muzzle. Ten feet away, it’s intoxicating. Especially if …