无心插柳柳成阴

wú xīn chā liǔ liǔ chéng yīnwuxinchaliuliuchengyin

1. lit. idly poke a stick in the mud and it grows into a tree to shade you
2. (fig.) unintentional actions may bring unexpected success
3. also written 無心插柳柳成蔭|无心插柳柳成荫

Study it in Yanamino