C     Plotting program for general purpose using postscript
      call init
      call viewport(0.2,0.2,0.8,0.8)
      call xyworld(-0.2,-0.2,1.2,1.2)
      call linewidth(2.0)
      call line1(0.5, 0.0, 0.5, 0.02)
      call line1(1.0, 0.0, 1.0, 0.02)
      call line1(0.0, 0.5, 0.02, 0.5)
      call line1(0.0, 1.0, 0.02, 1.0)
      call arrow1(-0.1, 0.0, 1.2, 0.0, 0.02)
      call arrow1(0.0, -0.1, 0.0, 1.2, 0.02)
      call textx(1.2,-0.02,1,'x')
      call textx(0.5,-0.02,3,'0.5')
      call textx(1.0,-0.02,3,'1.0')
      call texty(-0.02,1.2,1,'y')
      call texty(0.0,0.5,3,'0.5')
      call texty(0.0,1.0,3,'1.0')
      call textx(-0.06,-0.02,1,'O')
      call plotd1
      call fin
      stop
      end
c
      subroutine plotd1
      common /ndata/n,nx,ny,ns
      common /xydata/x(100),y(100)
c     call clip(-1.0,-1.0,1.0,1.0)
      write(1,*) ' 1.0 setlinewidth'
      write(1,*) ' 0.6 setgray'
      call linety(1)
      call linewidth(1.0)
      m=10
      do 50 ix=0,m
      do 50 iy=0,m
       x0=0.0+1.0*float(ix)/float(m)
       y0=0.0+1.0*float(iy)/float(m)
       dt=0.05
       dx=1.0
       dy=3.0*x0*y0
       ds=sqrt(dx**2+dy**2)
       if(ds.ne.0.0) then
       x1=x0+dx/ds*0.05
       y1=y0+dy/ds*0.05
       call arrow1(x0,y0,x1,y1,0.01)
       end if
   50 continue
      write(1,*) ' stroke '
      write(1,*) ' newpath'
      write(1,*) ' 0.4 setgray'
      write(1,*) ' 1.2 setlinewidth'
      call linety(1)
      n=40
      m=1
      do 10 ix=0,0
      do 10 iy=0,0
       x(0)=0.0
       y(0)=0.1
c      write(*,*) c1,c2
       dt=0.0128
       call plot(x(0),y(0),3)
        do 20 it=1,2*n
        x(it)= x(it-1)+(1.0)*(dt)
        y(it)= y(it-1)+(3.0*x(it-1)*y(it-1))*(dt)
        call plot(x(it),y(it),2)
   20 continue
c       write(1,*) ' stroke '
   10 continue
      return
      end