{HEAD ~ The beads} 21 are preferably {TAIL ~ commercial stock plastic beads} of the type commonly available for plastic injection molding of commercial plastic parts 
are preferably
{ HEAD ~ The beads } 21 are preferably { TAIL ~ commercial stock plastic beads } of the type commonly available for plastic injection molding of commercial plastic parts
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH