wherein * denotes {TAIL ~ the point} of attachment of T1 to COUP and ** denotes the point of {HEAD ~ attachment} to T2  
wherein * denotes { TAIL ~ the point } of attachment of T1 to COUP and * * denotes the point of { HEAD ~ attachment } to T2
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH