{HEAD ~ A block placement generator} arranges {TAIL ~ sets} of the interface objects into block configurations within the interface 
arranges
{ HEAD ~ A block placement generator } arranges { TAIL ~ sets } of the interface objects into block configurations within the interface
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH