+
+Manipulating the object tree
+----------------------------
+
+To change object relationships at run-time:
+
+ move object to parent_object ;
+ remove object ;
+
+To return the parent of an object (or nothing):
+
+ parent(object)
+
+To return the first child of an object (or nothing):
+
+ child(object)
+
+To return the adjacent child of an object's parent (or nothing):
+
+ sibling(object)
+
+To return the number of child objects directly below an object:
+
+ children(object)
\ No newline at end of file