{TAIL ~ Each conduit} has {HEAD ~ a corresponding coupling mechanism} which enables it to move up and down 
{ TAIL ~ Each conduit } has { HEAD ~ a corresponding coupling mechanism } which enables it to move up and down
TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH