| Class Summary | 
| ANode<T> | Represents the state of the owner binary tree structure. | 
| BiTree<T> | Models the binary tree structure using the state pattern and the visitor
 pattern. | 
| DatNode<T> | Stores data and represents a non-empty state. | 
| EmptyNode<T> | Represents the empty state of a BiTree. | 
| ToString<T> | Computes a String representation of the binary tree host so that it can be
 printed vertically. | 
| ToStringHelp<T> | Computes a String representation of the binary tree host so that it can be
 printed vertically, given a leftmost leading string for the two subtrees. |