And they sit at the bar and put bread in my jar / And say, Man, what are you doing here?

the flavor of a rose

The match of two finite line segments in 2 dimensions requires 2 translations, 1 rotation, 1 scale transformation; the order is here important, and these operators cannot commutate.

When they describe, for example, payment of cattle for a bride in East Africa, offering a gift in India to earn spiritual merit, exchanging favors between compadres in Middle America, giving a ceremonial necklace in return for an arm shell in the Trobriand kula ring, and potlaching each other by Kwakiutl chiefs, ethnographers are assuming the operation of some reciprocal principle.