Dirs: direction field
  d_t A = A*(1-A^2-B^2) + K * Lapl(A)
  d_t B = B*(1-A^2-B^2) + K * Lapl(B)
  K =     0.800000

  nSteps = 3000
  dt =     0.010000

A range = [   -1.5000 _     1.5000]dA range = [   -0.0803 _     0.0803]B range = [   -1.5000 _     1.5000]