The parameters are as follows:

**a**,**b**,**eta**are parameters of the equation.**delta**is a "small" parameter that sets when a simplified iteration scheme is used that is good only for small values of one of the fields (the scheme is used when the value is less than*delta*). Increasing*delta*to*10*increases the speed at the cost of faithfulness to the original equations.^{-2}**amp**is the amplitude of a sinusoidal forcing at one corner with frequency*0.5***speed**is a benign way of increasing the speed at the cost of jerkiness of the plotting: the iteration is done*speed*times between each plot update.- The two choices of
**plot type**show the concentrations of the two components involved in the reaction.

The system size is 64 along each edge. The mesh size *h* for the finite difference code is 0.5 and the time step *dt=0.05*.