-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