100 setxunit
7.5 setborder
90 setangle_repere
-0.5 2 setxrange
-1 1 setyrange
1 1 settkstep
.5 .5 setsubtkstep
0.5 0.5 setmkstep
ticks
subticks
marks
traceaxes
axesarrow
/R {settvar
#rpn#   2*Cos(t)/(Sin(t)+2)
} def
 0 2 pi mul  settrange
gsave
   .75 setlinewidth
   continu
   bleu
   (R) courbepolar
grestore