-1 8 setxrange
-1 9 setyrange
150 setheight
quadrillage
/A {0 0} def
/B {7 0} def
/C {7 8} def





[A B C] polygone

1.9 setlinewidth


[A B  C ] points

setTimesItalic
   (A) A dltext
   (B) B drtext
  
 (C) C urtext