{TAIL ~ This configuration} is established by means of {HEAD ~ the confocal paraboloids} 104 and 140 
{ TAIL ~ This configuration } is established by means of { HEAD ~ the confocal paraboloids } 104 and 140
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH