30 setxunit
tracerepere
marks
-2 4 setxrange
-4 4.5 setyrange
/A {2 -1} def
/B {2 1} def
/A1 {1 2} def
/A2 {3 -4} def
/B1 {-1 2} def
/B2 {3 4} def
[B B1 B2] polygone
[A1 A2] ligne
[B B1 B2 A A1 A2] points
(A) A drtext
(A') A1 drtext
(A") A2 urtext
(B) B drtext
(B') B1 drtext
(B") B2 urtext