The great poet Li Bai had trouble studying when he was a child. On his way out of school, he came across an old woman grinding needles with an iron pestle. This deeply touched him, so he finally studied hard and became successful in his studies. "As long as you work hard enough, an iron pestle can be ground into a needle" comes from this story. This sentence has also become a famous aphorism that encourages future generations to persevere in learning.

Mozhen Creek is at the foot of Elephant Er Mountain in Meizhou. Legend has it that Li Taibai was studying in the mountains, but he abandoned it before completing it. After crossing a stream, I met an old woman who was grinding an iron pestle and asked her, "I want to make a needle." Taibai understood what he meant and graduated. I said my surname was Wu. There is Wushi Rock next to Jinxi River.

I hope I can help you clear up your doubts.