the third light projecting portion is adapted to project the third visible light beam traveling vertically in {HEAD ~ the shape} of a cross consisting of {TAIL ~ a traversal beam} spreading along the line connecting the first optical beam pointer and the second optical beam pointer, and a longitudinal beam spreading perpendicular to the traversal beam, 
the third light projecting portion is adapted to project the third visible light beam traveling vertically in { HEAD ~ the shape } of a cross consisting of { TAIL ~ a traversal beam } spreading along the line connecting the first optical beam pointer and the second optical beam pointer , and a longitudinal beam spreading perpendicular to the traversal beam ,
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH