Everything that happens once can never happen again. But everything that happens twice will surely happen a third time. Paulo Coelho
To live alone one must be an animal or a god --says Aristotle. There is yet a third case one must be both --a philosopher. Friedrich Nietzsche
It is a maxim universally agreed upon in agriculture, that nothing must be done too late; and again, that everything must be done at its proper season; while there is a third precept which reminds us that opportunities lost can never be regained. Pliny the Elder
Two birds disputed about a kernel, when a third swooped down and carried it off. African Congo Proverb
When two dogs fight over a bone, a third one carries it away. Dutch Proverb
A good deal for two, is a clip on the ears of a third. Finnish Proverb