repeating {HEAD ~ the sequence} of steps through with {TAIL ~ respect} to subsequent substrate elements in the series 
repeating { HEAD ~ the sequence } of steps through with { TAIL ~ respect } to subsequent substrate elements in the series
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH