program anim_sin
      real xx(1000),yy(1000)
      real xxold(1000),yyold(1000)
      i_dummy=pgopen('/xwin')
      xleft=-14.0
      xright=14.0

      call pgenv(xleft,xright,-2.0,2.0,0,0)
      m=100
      dx=(xright-xleft)/(m-1)

      do j=1,100000

        do i=1,m
          xx(i)=xleft+(i-1)*dx
          yy(i)=sin(xx(i)+j*0.01)
        end do

        call pgbbuf
         call pgsci(0)        
         call pgline(m,xxold,yyold)
         call pgsci(1)
         call pgline(m,xx,yy)
        call pgebuf

        do i=1,m
          xxold(i)=xx(i)
          yyold(i)=yy(i)
        end do

      end do

      call pgclos
      end