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.

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