during the southern and northern dynasties period (420-589), there was a chinese painter called zhang sengyao. once, he visited a temple and painted four *s on the wall, but he gave none of them eyes. onlookers1 thought this odd, and asked why he hadn't painted in the eyes. he answered: "eyes are crucial for *s. with the eyes painted in, the *s would fly away." nobody beli*d this, so zhang sengyao took up his brush and added eyes to two of the *s. no sooner had he finished than the two *s flew into the sky amid a thunderstorm. the two without eyes remained paintings on the wall.
this idiom is used to describe how, when painting, writing or speaking, the addition of just one or two key brushstrokes, sentences, words or phrases could enhance2 the content.
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