The Multitype Fertility Model

1. The grid contains empty spots and two species (Green and Blue). Each species has two forms: Fertile (can reproduce) and Sterile (cannot reproduce).

2. Every living cell, regardless of species or fertility, dies at a fixed constant rate, leaving an empty spot.

3. Only Empty spots can generate new life. The chance of birth depends entirely on the number of Fertile neighbors nearby.

4. Sterile cells occupy space but do not help neighbors reproduce. They act as "bed-blockers" that dilute the local population's ability to grow.

5. When a Fertile neighbor reproduces into an empty spot, the new cell is usually Fertile, but there is a specific probability it will be born Sterile.

6. If an empty spot is bordered by both species, they compete to fill it. The species with the higher birth rate and more Fertile neighbors is more likely to win.