They heard a noise of mournful mewing, and looked down at the cats in the river below. A small black one, the probable mewer, was gazing up at them with such a sorrowful expression in its green eyes that my lady was wrung with pity.
Source: wiktionary
This supposedly demonstrates 'uncertainty' because one doesn't know if the cat is dead or alive until you peek inside. However, our version is more deterministic. There is no isotope-clock, no hydrocyanic acid. We drop a mewer in one of these reusable modules, close it tight, add just a limited supply of oxygen […]
Source: wiktionary