NTree<Vector3> vecTree = new vecTree(Vector3.zero);
// Add children to root node
vecTree.addChild(new Vector3(1f, 2f, 3f));
vecTree.addChild(new Vector3(4f, 5f, 6f));
// Add a child to first child of the root node [ the one that is (1,2,3) ]
vecTree.getChild(0).addChild(new Vector3(7f, 8f, 9f))