# set terminal pngcairo  transparent enhanced font "arial,10" fontscale 1.0 size 600, 400 
# set output 'spotlight.1.png'
unset border
set dummy u, v
unset key
set parametric
set view 90, 0, 1.6, 1
set view  equal xyz
set samples 95, 95
set isosamples 95, 95
set style data lines
set xyplane at 0
unset xtics
unset ytics
unset ztics
unset cbtics
unset rtics
set title "In interactive terminals,\nHot keys x/X and y/Y move red spotlight" 
set trange [ * : * ] noreverse nowriteback
set urange [ * : * ] noreverse nowriteback
set vrange [ * : * ] noreverse nowriteback
set xrange [ * : * ] noreverse writeback
set x2range [ * : * ] noreverse writeback
set yrange [ * : * ] noreverse writeback
set y2range [ * : * ] noreverse writeback
set zrange [ * : * ] noreverse writeback
set cbrange [ * : * ] noreverse writeback
set rrange [ * : * ] noreverse writeback
set pm3d depthorder 
set pm3d lighting primary 0.5 specular 0.2 spec2 0.5
set pm3d spotlight rgb 0xff0044 rot_x 35 rot_z 0 Phong 10.0
set colorbox vertical origin screen 0.9, 0.2 size screen 0.05, 0.6 front  noinvert bdefault
unset colorbox
NO_ANIMATION = 1
spot_x = 35
spot_z = 0
splot cos(u)*cos(v),cos(u)*sin(v),sin(u) with pm3d fc "gray"