applying a combination of high frequency ultrasound waves and pressure to {HEAD ~ the said pieces} of fabric, so overlapped and folded, along the layers of {TAIL ~ overlap} and fold 
applying a combination of high frequency ultrasound waves and pressure to { HEAD ~ the said pieces } of fabric , so overlapped and folded , along the layers of { TAIL ~ overlap } and fold
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH