Of course, the edge running parallel here to {HEAD ~ the outlet plane} of {TAIL ~ the tube} 20 can be brought back to the outlet plane step again by means of a curved path 
Of course , the edge running parallel here to { HEAD ~ the outlet plane } of { TAIL ~ the tube } 20 can be brought back to the outlet plane step again by means of a curved path
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH