Rough Dentogram ( clustering based on segment distance )

   PL492 495  
   !  
   4--PH482 491  
   !     
   !     PL468 473  
   !     !  
   !     1--PH460 467  
   !     !     
   3-----2-----PH474 479  
   !              
   5--------------PH496 511  
   !                 
   6-----------------PH511 525  
  /
 /