250 setwidth 250 setheight 7.5 setborder -1.2 1.2 setxrange -1.2 1.2 setyrange jpegmode /quadrillagegray 0.6 def .2 setquadrillagexstep .2 setquadrillageystep quadrillage 1 1 settkstep .5 .5 setsubtkstep 2 2 setmkstep ticks subticks marks traceaxes axesarrow /R {settvar t sin t sin mul t cos t cos mul add .1 200 pi add t mul sin mul add } def 0 2 pi mul settrange gsave 4 setcurvelinewidth continu magenta (R) courbepolar grestore