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