The relationship between snapshots is like that of a parent to a child. In the linear process, each snapshot has one parent and one child, except for the last snapshot, which has no children.

The snapshots taken form a tree. Each time you revert and take another, a branch (child) is formed.

In the process tree, each snapshot has one parent, but one snapshot may have more than one child. Many snapshots have no children.

You can revert to a parent or a child.