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