{TAIL ~ The segmentation} also may define {HEAD ~ points} at which aggregate outputs may be provided, and where checkpoints may be established 
{ TAIL ~ The segmentation } also may define { HEAD ~ points } at which aggregate outputs may be provided , and where checkpoints may be established
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH