[pstricks] series and multido

[Denis Vergès]

Hello
%%%%%%%%%%%%%%%%%%%%%%%%%%
\pscustom[linewidth=1.2pt,arrowscale=1.5]
{
    \code{/x 1 def
          /y  x 1 add ln  x 2 exp 2 div add def
              }
       \multido{\i=1+1}{4}
       {
           \moveto(!x y)
           \psline{->}(!x x)(!x y) \closepath
           \psline{->}(!x y)(!y y) \closepath
%% Here I want draw (with style dashed) vertical \psline from x-axis  
till $y = x$
           \code{/x y def
                 /y x 1 add ln  x 2 exp 2 div add def
                     }
       }
}

Thanks
Denis