-2 3 setxrange
-2.5 2.5 setyrange

150 setwidth
150 setheight

/A {2 2} def
/B {1 pi 5 mul 6 div polcar} def
/C {1 3 sqrt neg} def
/dt 20 def

.5 .5 setquadrillagestep
quadrillage
traceaxes
axesarrow
marks
unites
[A B C] (times2) plot

O B angle dt sub
O B angle dt add
O 1 Cercle

O C angle dt sub
O C angle dt add
O 2 Cercle

pointilles
[B B projy] ligne

setTimesItalic
   (A) A rtext
   (B) B ultext
   (C) C drtext