and im talking about all vehicles with wheels. the same situation and no common descent.this is the common similarity argument.
so how you can explain that in general all similar creatures (say mammals or reptiles) grouping together? similarity is clearly a good indication.
in any case as i said all creatures cant be equally similar to each other. thus in any case we will see a tree pattern. also remember that you cant prove that nested hierarchy doesnt exist in designed object. thus you cant say that designed objects dont show a nested hierarchy.