Source
%% auteur : Gilles Mora

-2 7 setxrange
-5 4.25 setyrange
30 setxunit
30 setyunit
/A{2 3} def
/B{0 0 } def
/C{5 0} def
/A'{B C 60 rotatepoint} def
/B'{C A 60 rotatepoint} def
/C'{A B 60 rotatepoint} def
[A B C] polygone
[A B C'] polygone
[B C A'] polygone
[A C B'] polygone
pointilles
[A A'] ligne
[B B'] ligne
[C C'] ligne
setTimes
(A) A  utext
(B) B  dltext
(C) C  drtext
(A') A'  drtext
(B') B'  drtext
(C') C'  utext