-6 6 setxrange
-1.5 6 setyrange

/fillstyle {hachure} def

/r 5 def
/x 3 def
/A {r neg 0} def
/B {r 0} def
/M {A x 0 addv} def

/d -.5 def    %%% le decalage pour les cotations
/A1 {A 0 d addv} def
/M1 {M 0 d addv} def
/A2 {A 0 2 d mul addv} def
/B2 {B 0 2 d mul addv} def

180 0 O r Cercle*
gsave
   blanc
   [A B] ligne
grestore

A1 M1 (<->) line
A2 B2 (<->) line

medium setlinewidth
180 0 O r Cercle
gsave
blanc
   newpath
   A moveto
   180 0 A M milieu x 2 div Cercle_
   closepath
   fill
grestore
180 0 A M milieu x 2 div Cercle

gsave
blanc
   newpath
   M moveto
   180 0 M B milieu M B distance 2 div Cercle_
   clip
   fill
grestore
180 0 M B milieu M B distance 2 div Cercle



setTimesItalic
   (A) A dltext
   (M) M drtext
   (B) B drtext
   (x) A1 M1 milieu utext
setTimes
   (10 cm) A2 B2 milieu utext