Thus, once {HEAD ~ an instrument} initially is placed in {TAIL ~ the holder}, each flap customizes itself to the shape of each instrument 
initially is placed in
Thus , once { HEAD ~ an instrument } initially is placed in { TAIL ~ the holder } , each flap customizes itself to the shape of each instrument
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH