%% auteur : gh
100 setxunit
-1 3 setxrange
-1 2 setyrange

/cosa {pi 6 div Cos} def
/sina {pi 6 div Sin} def
/cost {pi 3 div Cos} def
/sint {pi 3 div Sin} def
/B {0 0} def
/Omega {cosa sina} def
/A {2 cosa mul 2 sina mul} def
/u {cost sint} def
/M {O u 2 cosa mul mulv addv} def

16 setfontsize
setTimesItalic
(A) A crtext
(B) B dltext
(M) M uctext
setSymbol
   (W) Omega drtext

B Omega droite
[O M Omega A] points

1 setlinewidth
bleu
Omega 1 cercle

2 setlinewidth
rouge
B M (-) line
M A (-) line
B M A angledroit