%% taille de la fenetre
-4 5 setxrange
-4 5 setyrange
80 setxunit
%% definition des points
/A {1 1.732} def
/B {0 0} def
/C {2 0} def
/H {1 0} def
/E {-0.732 0} def
[A B C] polygone
[A B C E H] points
[E A] ligne
[E B] ligne
pointilles
[A H] ligne

setTimesItalic
   (A) A ultext
   (B) B ultext
   (C) C rtext
   (H) H dltext
   (E) E dltext