The error path includes {HEAD ~ a first sub path}, {TAIL ~ a second sub path}, a second synthesizer and a third sub path 
The error path includes { HEAD ~ a first sub path } , { TAIL ~ a second sub path } , a second synthesizer and a third sub path
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH