Source
18 setfontsize
-5 5 setxrange
-1 4 setyrange

/f {pop 1} def
50 setxunit

[1 1 .5 .5 .1 .1] {orange} Quadrillage
tracerepere
marks
gsave
   bleu
   1.75 setlinewidth
   {f} courbe
grestore

setTimesItalic
   (O) O drtext

<tex>
$$
   y = 1
$$
</tex>

/dx_boxit 2 def
/dy_boxit 2 def
/fillstyle {jaune fill} def
/linearc .05 def
boxit
-2 2 [2 dup] cctexlabel