An OrderedGroup guarantees children are rendered in first-to-last order
Unlike Group, BranchGroup, etc.
Good for avoiding Z-fighting artifacts
OrderedGroup extends the Group class
OrderedGroup adds no additional methods beyond those of the Group class
The OrderedGroup node guarantees that Java 3D will render
its children in their index order. Only the OrderedGroup node and its subclasses
make any use of the order of their children during rendering.