150 setwidth

/r 5 def
/cerc {O r} def
/A {85 cerc cpoint} def
/B {-152 cerc cpoint} def
/C {-20 cerc cpoint} def
/D {-75 cerc cpoint} def
B C A D interdroite /E defpoint

1.2 setlinewidth
cerc cercle

.8 setlinewidth

/fillstyle {.6 setgray fill} def
[B D E] polygone*
[A E C] polygone*

%[A B C] polygone
[B A] ligne


[A B C D O] points

setTimesItalic
   (O) O dltext
   (A) A urtext
   (B) B dltext
   (C) C drtext
   (D) D drtext
   (E) E drtext