# set terminal pngcairo  transparent enhanced font "arial,10" fontscale 1.0 size 600, 400 
# set output 'ttics.1.png'
unset border
set dummy t, y
set ttics format "%g°"
set grid polar 1.047198
set grid noxtics nomxtics noytics nomytics noztics nomztics rtics nomrtics \
 nox2tics nomx2tics noy2tics nomy2tics nocbtics nomcbtics
set grid layerdefault   linecolor rgb "gray"  linewidth 0.200 dashtype solid,  linecolor rgb "gray"  linewidth 0.200 dashtype solid
set raxis
unset key
set polar
set polar grid 24, 10 qnorm 1  theta [0:360]  r [0:*]
set size ratio 1 1,1
set style data lines
set mttics 3
unset xtics
unset ytics
set ttics axis in scale 1,0.5 nomirror norotate  autojustify
set ttics  norangelimit 0.00000,30  font ":Italic"
set ttics add  ("Ï€/2" 90.0000, "Ï€" 180.000, "3Ï€/2" 270.000)
set title "Angle labels (ttics) for polar plots" 
set title  offset character 0, 1, 0 font "" textcolor lt -1 norotate
set trange [ * : * ] noreverse nowriteback
set urange [ * : * ] noreverse nowriteback
set vrange [ * : * ] noreverse nowriteback
set xrange [ -6.10000 : 6.10000 ] noreverse nowriteback
set x2range [ * : * ] noreverse writeback
set yrange [ -6.10000 : 6.10000 ] noreverse nowriteback
set y2range [ * : * ] noreverse writeback
set zrange [ * : * ] noreverse writeback
set cbrange [ * : * ] noreverse writeback
set rrange [ 0.00000 : 6.10000 ] noreverse nowriteback
set colorbox vertical origin screen 0.9, 0.2 size screen 0.05, 0.6 front  noinvert bdefault
NO_ANIMATION = 1
plot t lt 3 lw 2, -t lt 4 lw 2