%auteur : Peric
28.45 setxunit
-1 5 setxrange
-1 5 setyrange

/A {2 4} def
/B {4 2} def
/C {2 0} def   
/D {0 0} def
/I {3 3} def
/J {3 1} def
/K {1 0} def
/L {1 2} def

(A) A [1.5 dup] ultext
(B) B [1.5 dup] crtext
(C) C [1.5 dup] drtext
(D) D [1.5 dup] dltext
(I) I [1.5 dup] urtext
(J) J [1.5 dup] drtext
(K) K [1.5 dup] dctext
(L) L [1.5 dup] ultext
[A B C D A ] ligne
gsave
pointilles
[I J] (->) ligne
[L K] (->) ligne
[A C] (->) ligne
[J K] ligne
[L I] ligne
grestore
A I 1 marked
I B 1 marked
B J 2 marked
J C 2 marked
C K 3 marked
K D 3 marked
D L 4 marked
L A 4 marked