the.com/interplay

Not interaction's weaker cousin — it's what happens when things change each other back.

means The way two or more things act on each other, each shifting in response to the other's moves.

from A 19th-century coinage built from the prefix 'inter-' (between, among) plus 'play' — in the sense of free, mutual movement, like the 'play' in a rope or a mechanism, the bit of give that lets parts move against each other. Not children's play, but the older sense of things moving freely in relation to one another.

vs interaction
interaction can be one-way; interplay never is
etymology
borrowed from stage directions, originally about actors
favorite habitat
light and shadow, nature and nurture, jazz solos
key test
if nothing bounces back, it is not interplay
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