[集腋成裘, jí yè chéng qiúㄐㄧˊ ㄧㄝˋ ㄔㄥˊ ㄑㄧㄡˊ] many hairs make a fur coat (成语 saw); many small contributions add up to sth big; many a mickle makes a muckle#113506
[变生肘腋 / 變生肘腋, biàn shēng zhǒu yèㄅㄧㄢˋ ㄕㄥ ㄓㄡˇ ㄧㄝˋ] lit. calamity in one's armpit (成语 saw); a major coup happening on one's doorstep; trouble or danger in one's own backyard#197077