This central spindle can be a solid post or it can be an annular shaft through {TAIL ~ the center} of which {HEAD ~ a light source} can be directed 
of
This central spindle can be a solid post or it can be an annular shaft through { TAIL ~ the center } of which { HEAD ~ a light source } can be directed
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL REL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH