program sinwaves
  use genplotting
  implicit none

  integer  foo, c
  real     phase
  call genp_init (0, 'WS/lissajous.scratch')

  do foo=1, 20
    phase = real(foo) * 0.314159
    c = 3 + mod(foo, 2)
    call do_lissajous (400, phase, c)
  enddo

  call genp_end (0)

contains
! ---------------------------------------------------------
subroutine do_lissajous (nbpass, phy, col)
  integer, intent(in)   :: nbpass, col
  real,    intent(in)   :: phy

  integer               :: idx
  real                  :: ridx, x, y

  do idx=0, nbpass
    ridx = 6.28318 * (real(idx) / real(nbpass))
    x = sin(ridx + phy)
    y = cos(ridx*3)

    if (idx .eq. 0) then
      call genp_move(x, y)
    else
      call genp_draw(x, y, col)
    endif

  enddo

end subroutine
! ---------------------------------------------------------
end program