-3.5 4.5 setyrange
-4.5 5.5 setxrange
35 setxunit
.5 .5 setquadrillagestep
quadrillage
/unites {} def
tracerepere
marks
/ymarkstyle {cltext} def


/B {-4 -3} def
/C {5 -1} def

[B C] points


1.2 setlinewidth
/arg {argc} def
[B .. -2.5 2.5 .. -2 3  {right} .. -1.5 1 .. -1 0 .. 1 -2  {right} .. 1.5 -1 .. 1.6 0 .. 3 2  {right} .. 3.7 0 .. C] draw

.6 setlinewidth
pointilles

setTimesItalic
   (O) O dltext