Mófǎng dàshī de fēnggé nòng bùhǎo jiù huàhǔ-lèiquǎn.
Imitating a master's style badly is like drawing a tiger and ending up with a dog.
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From 《后汉书·马援传》: Han general 马援 warned his nephews against imitating the reckless knight-errant 杜季良, saying they might 'draw a tiger and end up with a dog' - unable to match the original and only making themselves look foolish.