‘Uncle Dominic,’ I called out in my shrill voice. The table hushed, and my great-uncle's eyelids opened a crack. ‘Your stroboscope is like snow. There were footprints leading to the back door this morning when l got up, and I've just thought…’ but to my chagrin the relatives at once resumed their conversations in unnecessarily loud voices. I piped louder, but my ingenious explanation - that all the action happens between the footprints, so that only the moments of stillness are made visible by the snow - was drowned by my relatives' voices that rose with mine, fell briefly at intervals when they thought I'd given up, then rose in chorus again as I persisted, so that all my Uncle Dominic was allowed to hear were the disjointed words that rang out during the brief pauses.