The first two stages interpenetrate each other.

前两个阶段相。

However, if one of the particles, for example, is concave, like a crescent moon, then you can imagine that two adjacent particles could interpenetrate more tightly or fit more snugly with one another.

但是，例如，如果其中个粒子是凹的，就像新月样，那么想象两个相邻的粒子更紧密地相或更紧密地相配合。