The first two stages interpenetrate each other.

前两阶段相互渗透。

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，如是凹的，就像新月样，那么您可以想象两相邻的可以更紧密地相互渗透或更紧密地相互配合。