"A simple Punnett square. The columns show two alleles F (dominant) and f (recessive) in the 'male' gametes in the population pool. The rows show the same two alleles in the 'female' gametes of the population pool. For each allele, p and q represent their respective proportions in the population. The Punnett square is like a multiplication table where the each box is the product of the relevant row and column, and so it shows both the genotype that results and their proportions when gametes fuse. "