%!

72 72 scale
0.01 setlinewidth
6 6 translate




newpath
0 1.5 0.6 90 270 arc
stroke

newpath
0 -1.5 0.6 90 270 arc
stroke









newpath
0 3 moveto
0 -3 lineto
0.2 -3 lineto
0.2 3 lineto
0 3 lineto
0 0 0 setrgbcolor
stroke

newpath
0 3 moveto
0 -3 lineto
0.2 -3 lineto
0.2 3 lineto
0 3 lineto
0 1 0 setrgbcolor
fill

newpath
0 0 0 setrgbcolor
-0.5 -1.5 2 151 209 arc
0 0 0 setrgbcolor 
stroke

newpath
0 0 0 setrgbcolor
-4 -1.5 2 331 389 arc
0 0 0 setrgbcolor 
stroke


%single red line without lens
newpath
1 0 0 setrgbcolor
-2 1.5 moveto
0 1.5 lineto
stroke


%red lines entering lens
newpath
-4 -0.55 moveto
-2.25 -0.55 lineto
stroke

newpath
-4 -1 moveto
-2.45 -1 lineto
stroke

newpath

-4 -1.5 moveto
0 -1.5 lineto
stroke

newpath
-4 -2 moveto
-2.45 -2 lineto
stroke

newpath
-4 -2.45 moveto
-2.25 -2.45 lineto
stroke

%red lines exiting lens
newpath
-2.25 -0.55 moveto
0 -1.5 lineto
stroke

newpath
-2.45 -1 moveto
-2 -1.05 lineto
0 -1.5 lineto
stroke

newpath
-2.45 -2 moveto
-2 -1.95 lineto
0 -1.5 lineto
stroke

newpath
-2.25 -2.45 moveto
0 -1.5 lineto
stroke


%arrows
newpath
-1.5 1.6 moveto
-1.4 1.5 lineto
-1.5 1.4 lineto
stroke

newpath
-3.5 -0.45 moveto
-3.4 -0.55 lineto
-3.5 -0.65 lineto
stroke

newpath
-3.5 -0.9 moveto
-3.4 -1 lineto
-3.5 -1.1 lineto
stroke

newpath
-3.5 -1.4 moveto
-3.4 -1.5 lineto
-3.5 -1.6 lineto
stroke

newpath
-3.5 -1.9 moveto
-3.4 -2 lineto
-3.5 -2.1 lineto
stroke

newpath
-3.5 -2.35 moveto
-3.4 -2.45 lineto
-3.5 -2.55 lineto
stroke




/Helvetica-Bold findfont
11 72 div scalefont
setfont

-0.02 -3.2 moveto
0 0 0 setrgbcolor
(leaf) show

-2.38 -2.65 moveto
(lens) show

-5.3 -1.5 moveto
(light source) show

-3 1.5 moveto
(light source) show


showpage