Diagram 4: Invalid Taxonomy

• Children of same parent with same name

                                   ""
                                    |
                      ----------------------------------------------------
                      |                            |            |        |
                    Alpha                        Beta         Delta    Delta  <-- invalid
                      |                            |            |
           -------------------------         ------------       |
           |                       |         |          |       |
        Epsilon                  Zeta       Eta       Theta   Iota
           |                       |                            |
           |                 ------------                       |
           |                 |          |                       |
         Kappa            Lambda        Mu                      Nu