{TAIL ~ The belt} is toothed on {HEAD ~ one side} and not on the other side so that some slippage can occur 
{ TAIL ~ The belt } is toothed on { HEAD ~ one side } and not on the other side so that some slippage can occur
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH