Lotka: Lotka-Volterra predator/prey system
  d_t A = A - A*B + K * Lapl(A)
  d_t B = A*B - B + K * Lapl(B)
  K =     0.200000

  nSteps = 100
  dt =     0.001000

A range = [   -1.0000 _     3.0000]dA range = [   -6.6323 _     6.6323]B range = [   -1.0000 _     3.0000]