
Walk the ownership tree printing all elements.
 anonymous element
   Part Tree Example
     Electrical
     Mechanical
     Automobile
       Drive Train
         Battery
         Motor
       Chassis
         Suspension
         Body

Show part decomposition.
 Automobile
   Drive Train
     Battery
     Motor
   Chassis
     Suspension
     Body

Show all electrical parts.
-  Battery
-  Motor

Show all mechanical parts.
-  Suspension
-  Body
