All flow-objects which result from processing the grove,
form this flow-object-tree.
The structures of both grove and flow-object-tree are equivalent.
The flow-object which results from processing the root, is the root of the
flow-object-tree (e.g. cookbook).
If there are no formatting specifications which are applied to a node (e.g. recipe),
the node's children (ingredient) are directly applied to its parent node (cookbook).
The reason you will find on the next page.
The data is directly attached to its parent nodes.