Time is like a river.
Because analogies depend on the concept as if , they often take the form of metaphors and similes. Mathematics and logic. The resemblance in this instance is the second item in each pair is twice the first item . All subsequent uses of the word and idea stem from this use. If a sheep has four legs, a head, and a tail, and a cow has the same, then the cow may also have eyes, ears, and skin, just like the sheep.