%% auteur : Florent Braisaz

-4.5 4.5 setxrange
-3.5 4.5 setyrange

15 setxunit

/A {-4 -2} def
/B {-2 2} def
/C {4 2} def
/D {2 -2} def
/O {0 0} def

gsave
bleu
D A B 1 (-) tripointarc
B C D 1 (-) tripointarc
A B C .75 (=) tripointarc
C D A .75 (=) tripointarc
grestore

gsave
1.25 setcurvelinewidth
[A B C D] polygone
grestore

gsave
rouge
[A D B C]{1 marked} dapply
[A B C D]{2 marked} dapply
[A O O C]{3 marked} dapply
[B O O D]{4 marked} dapply
grestore

pointilles
[B D] ligne
[A C] ligne