{HEAD ~ A belt structure} conveys the block of material from the first end of {TAIL ~ the conveyor} over the second end of the conveyor 
{ HEAD ~ A belt structure } conveys the block of material from the first end of { TAIL ~ the conveyor } over the second end of the conveyor
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH