-4.5 3.5 setxrange
-2.5 2.5 setyrange

/A {0.5 1} def
/B {-0.5 -1} def
/C {1 2} def
/D {-1 -2} def
/E {3 1} def
/F {-3 1} def
/G {2 -1} def
/H {-4 -1} def

[C D] ligne
[E F] ligne
[G H] ligne


O point


F A B  0.3 (-) tripointarc
G B A  0.3 (-) tripointarc

O B 1 marked
O A 1 marked


setTimesItalic
   (A) A drtext
   (B) B drtext
   (z') C crtext
   (z) D crtext
   (x') E dctext
   (x) F dctext
   (y') G dctext
   (y) H dctext
   (O) O crtext