The grid is repeatedly updated using the following equations to update the concentrations of A and B in each cell, and model the behaviors described above. Some typical values used, for those interested, are: DA=1.0, DB=.5, f=.055, k=.062 (f and k vary for different patterns), and Δt=1.0. The Laplacian is performed with a 3x3 convolution with center weight -1, adjacent neighbors .2, and diagonals
![Reaction-Diffusion Tutorial](https://cdn-ak-scissors.b.st-hatena.com/image/square/5938ca78ed8b7bbafcc0db13dfd40990696e97a3/height=288;version=1;width=512/http%3A%2F%2Fwww.karlsims.com%2Frd-kf-examples.png)