200 setxunit
7.5 setborder
90 setangle_repere
-0.5 0.5 setxrange
-1 0.5 setyrange
0.1 0.1 settkstep
.5 .5 setsubtkstep
0.5 0.5 setmkstep
ticks
ysubticks
marks
traceaxes
axesarrow
/R {settvar
    t Sin 2 t mul Cos mul
} def
  0  2 pi mul settrange
gsave
   .75 setlinewidth
   continu
   bleu
   (R) courbepolar
grestore