200 setwidth
200 setheight

-.5 1.5 setxrange
-.5 1.5 setyrange

/f {dup mul} def

tracerepere
marks
0 1 {f} Hachcourbe

gsave
   pointilles
   [1 dup 0 exch dup f] ligne
grestore

medium setlinewidth
{f} courbe

setTimesItalic
   (y = x) 1.1 1.2 ultext
   (2) exposant
   (O) O dltext