What does ha mean by other girls being made of bamboo Inside out and back again?

In "Inside Out and Back Again" by Thanhha Lai, the phrase suggests that the other girls are strong yet flexible, much like bamboo, which can bend without breaking. This comparison highlights their resilience and adaptability in the face of challenges. It also contrasts with the protagonist's own feelings of insecurity and vulnerability as she navigates her new environment. The imagery of bamboo symbolizes both strength and the ability to endure hardships.