The particles in each bin are split or merged to keep an equal number in each bin. Here we have 10 bins. The stochastic simulation can be merged with the solution of the associated Fokker-Planck equation. We see particles emerge under the blanket representing the probability density function. The little spheres on each molecule must align to react.
Stochastic simulation shows very few eventual reactions.
One reactant is shrunked for clarity. Many reactions are observed during stochastic simulation.