#!/usr/local/bin/gnuplot -persist
# set terminal pngcairo  transparent enhanced font "arial,10" fontscale 1.0 size 600, 400 
# set output 'ttics.2.png'
set border 4096 front lt black linewidth 1.000 dashtype solid
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   lt 0 linecolor 0 linewidth 0.500,  lt 0 linecolor 0 linewidth 0.500
set raxis
unset key
set polar
set size ratio 1 1,1
set style data lines
set mttics 3.000000
unset xtics
unset ytics
set ttics axis in scale 1,0.5 nomirror rotate by -270  autojustify
set ttics  norangelimit 0.00000,30 font ":Italic"
set ttics add  ("π/2" 90.0000, "π" 180.000, "3π/2" 270.000)
set title "Polar plot with border and rotated labels for ttics" 
set title  offset character 0, 1, 0 font "" textcolor lt -1 norotate
set xrange [ -6.50000 : 6.50000 ] noreverse nowriteback
set x2range [ * : * ] noreverse writeback
set yrange [ -6.50000 : 6.50000 ] noreverse nowriteback
set y2range [ * : * ] noreverse writeback
set zrange [ * : * ] noreverse writeback
set cbrange [ * : * ] noreverse writeback
set rrange [ 0.00000 : 6.50000 ] 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