-2 6 setxrange
-1 5 setyrange
30 setxunit

10 setfontsize
/A {0 0} def
/B {4 0} def
/S {0 2} def
/T {4 3} def

1.2 setlinewidth
[S A B T] ligne
[S T] {times2} plot

setTimesItalic
   (A) A dltext
   (B) B drtext
   (S) S ultext
   (T) T urtext